When the first armored vehicles of Russia's invading army reached the heart of Chernobyl nuclear plant on the afternoon of Feb. 24, they encountered a Ukrainian unit charged with defending the notorious facility.
In less than two hours, and without a fight, the 169 members of the Ukrainian National Guard laid down their weapons. Russia had taken Chernobyl, a repository for tonnes of nuclear material and a key staging post on the approach to Kyiv.
The fall of Chernobyl, site of the world's worst nuclear disaster, stands out as an anomaly in the five-month old war: a successful blitzkrieg operation in a conflict marked elsewhere by a brutal and halting advance by Russian troops and grinding resistance by Ukraine.
Now a Reuters investigation has found that Russia's success at Chernobyl was no accident, but part of a long-standing Kremlin operation to infiltrate the Ukrainian state with secret agents.
Five people with knowledge of the Kremlin's preparations said war planners around President Vladimir Putin believed that, aided by these agents, Russia would require only a small military force and a few days to force Ukrainian President Volodymyr Zelenskyy's administration to quit, flee or capitulate.
Through interviews with dozens of officials in Russia and Ukraine and a review of Ukrainian court documents and statements to investigators, related to a probe into the conduct of people who worked at Chernobyl, Reuters has established that this infiltration reached far deeper than has been publicly acknowledged. The officials interviewed include people inside Russia who were briefed on Moscow's invasion planning and Ukrainian investigators tasked with tracking down spies.
"Apart from the external enemy, we unfortunately have an internal enemy, and this enemy is no less dangerous," the secretary of Ukraine's National Security and Defense Council, Oleksiy Danilov, said in an interview.
At the time of the invasion, Danilov said, Russia had agents in the Ukrainian defense, security and law enforcement sectors. He declined to give names but said such traitors needed to be "neutralized" at all costs.
Ukraine's State Bureau of Investigation is conducting a probe into whether the National Guard acted unlawfully by surrendering its weapons to an enemy, a local official told Reuters. The State Bureau of Investigation didn't comment. The National Guard defended the actions of its unit at the plant, pointing to the risks of conflict at a nuclear site.
Court documents and testimony, reported here for the first time, reveal the role played by Chernobyl's head of security, Valentin Viter, who is in detention and is being investigated for absenting himself from his post. An extract from the state register of pre-trial investigations, seen by Reuters, shows Viter is also suspected of treason, an allegation his lawyer says is unfounded. In a statement to investigators, Viter said that on the day of the invasion he spoke by phone with the National Guard unit commander. Viter advised the commander not to endanger his unit, telling him: "Spare your people."
One source with direct knowledge of the Kremlin's invasion plans told Reuters that Russian agents were deployed to Chernobyl last year to bribe officials and prepare the ground for a bloodless takeover. Reuters couldn't independently verify the details of this assertion. However, Ukraine's State Bureau of Investigation has said it is investigating a former top intelligence official, Andriy Naumov, on suspicion of treason for passing Chernobyl security secrets to a foreign state. A lawyer for Naumov declined to comment.
At a national level, sources with knowledge of the Kremlin's plans said Moscow was counting on activating sleeper agents inside the Ukrainian security apparatus. The sources confirmed Western intelligence reports that the Kremlin was lining up Oleg Tsaryov, a hotelier, to lead a puppet government in Kyiv. And a former Ukrainian prosecutor general disclosed to Reuters in June that Ukrainian politician Viktor Medvedchuk, a friend of Putin, had an encrypted phone issued by Russia so he could communicate with the Kremlin.
Tsaryov said the Reuters account of how Moscow's operation overall unfolded "has very little to do with reality." He did not address his relationship with the Kremlin. A lawyer for Medvedchuk declined to comment. Medvedchuk is in a Ukrainian jail awaiting trial on treason charges that pre-date the Russian invasion.
Though Russia captured Chernobyl, its plan to take power in Kyiv failed. In many cases, the sleeper agents Moscow had installed failed to do their job, according to multiple sources in Russia and Ukraine. Ukraine Security Council Secretary Danilov said the agents and their handlers believed Ukraine was weak, which was "a total misconception."
People the Kremlin counted on as its proxies in Ukraine overstated their influence in the years leading up to the invasion, said four of the sources with knowledge of the Kremlin's preparations. The Kremlin relied in its planning on "clowns – they know a little bit, but they always say what the leadership wants to hear because otherwise they won't get paid," said one of the four, a person close to the Moscow-backed separatist leadership in eastern Ukraine.
Putin now finds himself in a protracted, full-scale war, fighting for every inch of territory at huge cost.
But the Russian intelligence infiltration did succeed in one way: It has sown mistrust inside Ukraine and laid bare the shortcomings of Ukraine's near 30,000-strong Security Service of Ukraine, or SBU, which shares a complicated history with Russia, and is now tasked with hunting down traitors and collaborators.
This internal Ukrainian turmoil burst into partial view on July 17. In a video address to the nation, President Zelenskyy suspended SBU head Ivan Bakanov, whom he has known for years, citing the large number of SBU staff suspected of treason. Ukrainian law enforcement sources told Reuters that some SBU staff recounted in conversation with them that they were unable to reach Bakanov for several days after Russia invaded, adding to a sense of chaos in Kyiv. Bakanov didn't respond to Reuters' requests for comment.
Zelenskyy also said 651 cases of alleged treason and collaboration have been opened against individuals involved in law enforcement and in the prosecutor's office. More than 60 officials from the SBU and the prosecutor general's office are working against Ukraine in Russian-occupied zones, Zelenskyy added.
Asked to comment on Reuters' findings, the Ukrainian presidential administration, the SBU and the prosecutor general's office did not respond. Kremlin spokesman Dmitry Peskov said: "All these questions have no relation whatsoever to us, therefore there is nothing for us to comment on here." The Russian intelligence agency, the FSB, and the defense ministry did not respond to Reuters' questions.
Moscow's spy apparatus has been intertwined with Chernobyl for decades. After the 1986 disaster, when a reactor blew up scattering radioactive clouds across Europe, the Soviet KGB stepped in. More than 1,000 KGB staff took part in the clean-up, according to a declassified internal memo to a Ukrainian government minister, dated 1991. Then-KGB boss Viktor Chebrikov ordered his officers to recruit agents among the plant's staff and instructed that a KGB officer should hold the post of deputy boss of the plant in charge of security, according to another memo - an internal KGB communication from 1986.
Even after Ukraine became independent in 1991, Moscow's spy chiefs remained powerful there. The first head of Ukraine's domestic intelligence service was Nikolai Golushko, who started his career in Soviet Russia. Before his appointment he led the Ukraine arm of the Soviet KGB. Golushko kept most of the Soviet-era officers in their jobs, he wrote in a 2012 memoir.
After four months as Ukraine's spy chief, Golushko moved back to Moscow to rejoin KGB headquarters, and in 1993 became head of Russia's newly created Federal Counter-Intelligence Service, precursor to today's FSB.
In Moscow, Golushko received a visit from the deputy head of Ukraine's State Security Service, Golushko wrote in the memoir. He recalled how Oleg Pugach, the Ukrainian official, asked for Golushko's help finding fabric to make the uniforms for Ukraine's intelligence officers. Golushko also wrote that Kyiv, short of its own resources and expertise, signed deals under which the SBU agreed to share intelligence information with Moscow. In exchange, Moscow provided supplies, technology and expert help with investigations. Reuters approached Golushko for comment. A colleague from an intelligence veterans' group told Reuters Golushko, now 85, was in ill health and could not answer questions. Reuters was unable to reach Pugach and couldn't independently confirm Golushko's account.
Intelligence officers working at Chernobyl officially became part of Ukraine's security apparatus in 1991, but they continued to take orders from Moscow, said the person with direct knowledge of the invasion plan. "In effect, these were FSB employees," said the person. The SBU did not respond to questions about Chernobyl or historical ties to Russian intelligence.
The Chernobyl nuclear plant is a vast facility. A giant steel structure encases Reactor No. 4, ground zero of the 1986 disaster. The plant lies just 10 kilometers at the closest point from the border with Belarus, in a dense and highly irradiated forest. Russia's war planners considered control of Chernobyl to be strategically important because it sat on the shortest route for their advance on Kyiv, according to Western military analysts.
The source with direct knowledge of the invasion plan said that in November 2021 Russia started sending undercover intelligence agents to Ukraine, tasked with establishing contacts with officials responsible for securing the Chernobyl power plant. The agents' goal was to ensure there would be no armed resistance once Russian troops rolled in. The source said Chernobyl also served as a drop-off point for documents from SBU headquarters. In return for payment, Ukrainian officials handed Russian spies information about Ukraine's military readiness.
Reuters could not independently verify details of the source's account, and neither Ukraine's State Bureau of Investigation nor the SBU responded to the news agency's questions. But a review of Ukrainian testimony and court documents and an interview with a local official show that Kyiv is conducting at least three investigations into the conduct of people who worked at Chernobyl. The investigations have identified at least two people suspected of providing information to Russian agents or otherwise helping them seize the plant, according to these documents.
One of the men suspected by Ukrainian prosecutors and investigators of helping Russian forces is Valentin Viter, a 47-year-old colonel in the SBU. At the time of the Russian invasion, Viter was the deputy general-director of the plant responsible for its physical protection.
In May last year, Viter oversaw a routine training exercise that was meant to simulate an attack by armed saboteurs. Armed members of the National Guard unit that protects Chernobyl took part, and rehearsed repelling the attackers by force. Viter said the exercise was a success, according to a video interview posted shortly afterwards on the plant's website. He also said he hoped Chernobyl's security team would "not need to apply the knowledge and skills we acquired in a real-life situation."
Viter was seconded from the SBU to work at Chernobyl as security chief in mid-2019, according to a statement he gave to investigators. In a further statement, he said that on Feb. 18 this year – six days before the Russian invasion – he went on sick leave with a respiratory problem.
By then, Russia was bolstering its troops in Belarus in preparation for an invasion, U.S. officials said at the time. Satellite images shot by U.S. satellite imagery company Maxar on Feb. 15 showed a military pontoon bridge under construction across the Pripyat River in Belarus, north of the power plant. Ukraine's police, and the SBU, were on heightened alert in response to the Russian threat, and the national police chief said in a statement at the time that security was reinforced at the Chernobyl plant.
On the morning of the Russian invasion, Feb. 24, Viter said, in a statement to investigators, that he was at his home in Kyiv. He telephoned the head of the Chernobyl National Guard unit, who was at his post. By then, people at the plant knew a column of Russian armored vehicles was heading their way.
Viter, according to his testimony to Ukrainian investigators, told the commander, in Russian: "Spare your people." Viter had no official authority over the National Guard, and Reuters could not determine whether the commander was heeding Viter's words when the unit surrendered after discussions with the Russian invaders. A National Guard statement identified the unit commander as Yuriy Pindak.
When the Russian soldiers finally retreated from Chernobyl after a 36-day occupation, they took Pindak and most of his unit away as captives. Ukraine says the guards are being held in Russia or Belarus. Russian officials did not comment on the unit's whereabouts.
Ukraine's State Bureau of Investigation is conducting a probe into whether the National Guard broke the law by laying down arms, said Yuriy Fomichev, mayor of the town of Slavutych where most of the Chernobyl workers live. Fomichev said he was not aware of anyone having been charged. The State Bureau of Investigation didn't respond to Reuters' questions about the matter.
The National Guard declined to comment on the actions of individual commanders and members of the unit tasked with protecting Chernobyl. "Fighting on the territory of nuclear facilities is prohibited by the Geneva Convention," it said, adding that this was "one of the reasons" why there was no heavy fighting at the site. It referred questions about any investigation to the Bureau.
Article 56 of an additional protocol to the Geneva Conventions states that nuclear power plants and other dangerous installations should not be attacked.
Viter was arrested in western Ukraine and is now in pre-trial detention there on suspicion of absenting himself from his post. An extract from the court's register, seen by Reuters, shows that law enforcement agents have initiated a second investigation into Viter for suspected treason by "deliberately assisting the military units of the aggressor country, the Russian Federation, in carrying out subversive activities against Ukraine." They have yet to uncover evidence tying him to Russian special services.
Viter has said in court statements that he fled Kyiv for the safety of his family two days after Chernobyl was seized but tried to stay in contact with colleagues at the plant.
His lawyer, Oleksandr Kovalenko, said Viter had a legitimate reason for being off work and was unaware that he should stay at Chernobyl. The lawyer said any treason allegation was unfounded and Viter had not been served with a letter of suspicion, a step which usually precedes charges. According to the lawyer, Viter said "Spare your people" to remind the National Guard commander that many people depended on him. Viter did not discuss surrender, Kovalenko said. He added that investigators had not asked Viter about any exchange of documents at Chernobyl.
Cash and emeralds
The extent to which Russia infiltrated Chernobyl has focused Ukrainian authorities' attention on the SBU, the agency Viter worked for, sources said. In particular, military prosecutors on Viter's case are interested in his connection to a former Ukrainian official called Andriy Naumov, according to sources with knowledge of the investigation and a transcript of Viter's questioning seen by Reuters.
Previously an official in the Ukrainian prosecutor's office, by 2018 Naumov had been appointed head of COTIZ, a state enterprise responsible for estate-management of the radioactive exclusion zone around Chernobyl. A major part of COTIZ's role was to promote "extreme tourism" in the exclusion zone, but the enterprise also had a role in keeping the site secure, according to its website.
After his stint at Chernobyl, Naumov was made the head of the SBU's department of internal security, a division that investigates other officers suspected of criminal activity. Last year, the agency said it thwarted an assassination attempt on Naumov by other SBU officers. Naumov was later fired as department chief, according to Ukrainian media outlet Ukrainska Pravda and a law enforcement source.
Naumov vanished shortly before the invasion, a person in law enforcement said. He eventually turned up in Serbia in June. A Serbian police statement issued on June 8 said police and anti-corruption agents had arrested a Ukrainian citizen identified by the initials "A.N." on the border with North Macedonia. He had been trying to cross into North Macedonia from Serbia. A search of the BMW in which he was a passenger uncovered $124,924 and 607,990 euros in cash, plus two emeralds, the statement said. It said the individual and the unnamed driver of the BMW, who was also detained, were suspected of intending to launder the cash and emeralds, which police believe originated from criminal activities. Volodymyr Tolkach, Ukraine's ambassador to Serbia, publicly confirmed the arrested man was Naumov.
The State Bureau of Investigation confirmed a local media report that it is conducting a pre-trial investigation into Naumov for state treason. It said it was looking into whether Naumov collected information on the security set-up at Chernobyl while working at the plant and later at the SBU and passed it to a foreign state. The statement did not say what grounds it had for suspecting he passed on secrets or if it had specific evidence linking him to Russia.
On March 31, President Zelenskyy issued a decree stripping Naumov of his brigadier-general rank. The same day, the Ukrainian president announced in an emotional address that Naumov and another SBU general were "traitors" who violated their oath of allegiance to Ukraine. Zelenskyy did not make reference to Chernobyl.
Naumov remains in detention in Serbia and could not be reached for comment. His lawyer in Serbia, Viktor Gostiljac, declined to comment. The SBU did not reply to questions about Naumov.
For Russia's war planners, seizing Chernobyl was just a stepping stone to the main objective: taking control of the Ukrainian national government in Kyiv. There, too, the Kremlin expected that undercover agents in positions of power would play a crucial part, according to four sources with knowledge of the plan.
Yuriy Lutsenko, who served as Ukraine's prosecutor general from 2016 until 2019, revealed to Reuters that at the time he left the role "hundreds" of Defense Ministry employees were under surveillance, approved by his office, because they were suspected of ties to the Russian state. Lutsenko said he believed there were similar numbers of suspected spies in other ministries.
Russia's war planners were also counting on other allies to help in the takeover, five sources said.
One of the most visible loyalists was Viktor Medvedchuk, a leader of Ukraine's Opposition Platform – For Life party. Putin is god-father to one of Medvedchuk's children. Since 2014, Medvedchuk has been a vocal opponent of the popular protests that called for closer ties to the European Union.
Medvedchuk was charged with state treason on May 11, 2021. Investigators from the SBU alleged at the time that Medvedchuk passed secret details about Ukrainian military units to Russian officials, and intended to recruit Ukrainian agents and covertly influence Ukrainian politics. The day before the invasion, he left his home in Kyiv and was planning on leaving the country, in violation of the terms of his bail, according to the SBU.
Medvedchuk was detained on April 12, Zelenskyy announced that day. Zelenskyy immediately posted pictures of him handcuffed, in Ukrainian military fatigues and looking bedraggled. Medvedchuk has since been in detention.
Medvedchuk has denied the treason charges, saying they were falsified and part of a political plot against him. Kremlin spokesman Peskov told reporters on April 13 Medvedchuk had no back-channel communication with the Russian leadership.
Lutsenko, the former Ukraine prosecutor general, told Reuters that before the Russian invasion, Medvedchuk used an encrypted telephone that was issued to him by the Kremlin, equipment reserved only for the most senior Russian officials and pro-Russian separatist leaders. Lutsenko said Ukrainian investigators had managed to hack the encrypted phone system, without disclosing what they found.
Medvedchuk's lawyer, Tetyana Zhukovska, declined to comment until a court has handed down a decision in the case. The Ukrainian prosecutor's office did not comment.
Another key figure, according to three sources familiar with the Russian plans, was Oleg Tsaryov, a square-jawed 52-year-old former member of Ukraine's parliament. He was picked by Kremlin invasion planners to lead the new interim government they planned to install, these sources said. Their comments are the first confirmation from within Russia of U.S. intelligence assessments, reported by the Financial Times earlier this year, that Moscow was considering putting Tsaryov in a leadership role in a puppet government in Kyiv.
Tsaryov has been under Ukrainian and U.S. sanctions since 2014, when, after a bid to win election as Ukrainian president collapsed, he headed up a body called "Novorossiya," or New Russia. The group pushed the idea of turning southeastern Ukraine into a separate pro-Russian statelet. By the start of this year, he was in Russian-annexed Crimea, where he owns two hotels.
In the early hours of Feb. 24, at the start of the invasion, Tsaryov told his more than 200,000 Telegram followers he had crossed into Kyiv-controlled territory. "I'm in Ukraine. Kyiv will be free from fascists."
But Zelenskyy did not capitulate. Any expectations in Moscow that he would flee Kyiv or negotiate a deal that would cede to Russia's demands soon evaporated. In the weeks that followed, Ukrainian forces halted Russian troops' advance on Kyiv.
Tsaryov never made it to the capital. On June 10, he posted an advertisement to his Telegram followers for his seaside hotel in Crimea, where a one-night stay costs 1,500 rubles ($28) per person per night. Tsaryov is now spending his time in Crimea with visits to Moscow, according to his social media posts.
Paranoia and mistrust
Russia's campaign of infiltration did, however, stir suspicion and mistrust at some levels of the Ukrainian state, which hampered its ability to govern, especially in the first few days after the invasion.
One stark incident that fueled the tensions in Kyiv's power corridors related to the death in early March of Denys Kirieiev, a former bank executive, several sources said. He was a member of the Ukrainian delegation that took part in short-lived talks with Russian negotiators on the Ukraine-Belarus border, starting on Feb. 28. A photograph showed Kirieiev sitting alongside Ukrainian officials at the negotiating table.
An advisor to the Zelenskyy administration said, in an online interview, that officers from the SBU shot Kirieiev while trying to arrest him as a Russian spy.
But Ukraine's Military Intelligence Agency said Kirieiev was its employee and intelligence officer, and that he died a hero while conducting an unspecified special assignment defending Ukraine. A source close to the Ukrainian military told Reuters that Kirieiev was indeed a spy working for Ukraine. He had access to the highest levels of the Russian leadership, this source said, and was feeding back valuable information on invasion plans and other matters to his handlers in Kyiv.
Amid the chaos early in the war, Bakanov, then the head of the SBU, left Kyiv for at least three days after the Russian invasion, according to three people in Ukrainian law enforcement. Two of these people said some SBU staff recounted they were unable to reach Bakanov for several days after Russia invaded. In suspending Bakanov on July 17, Zelenskyy cited an article in Ukraine's Armed Forces statute, under which servicemen can be relieved of their duties for improper conduct leading to casualties or a threat of casualties.
Bakanov and the SBU did not respond to Reuters' questions.
Zelenskyy, in his speech, stressed the toll Russian infiltration was taking on his embattled country by speaking of the numerous officials who have been accused of betraying Ukraine.
"Such an array of crimes against the foundations of the national security of the state ... poses very serious questions to the relevant leaders," Zelenskyy said.
"Each of these questions will receive a proper answer."