Jens Stoltenberg, NATO Secretary General, speaks at a press statement at the beginning of the informal meeting of EU defence…
FILE - Jens Stoltenberg, NATO Secretary-General, speaks at a press statement in Berlin, Germany, Aug. 26, 2020.

MOSCOW - After an urgent meeting of NATO ambassadors on Friday to discuss the poisoning of Russian opposition leader Alexei Navalny, the allies said Russia must fully cooperate in an impartial investigation under the supervision of the Organization for the Prohibition of Chemical Weapons.

Speaking to reporters after the meeting in Brussels, NATO Secretary-General Jens Stoltenberg said, "Any use of chemical weapons shows a total disrespect for human lives and is an unacceptable breach of international norms and rules."

FILE - Russian opposition politician Alexei Navalny takes part in a rally in Moscow, Feb. 29, 2020.

NATO members agreed that Russia faces serious questions it must answer, Stoltenberg said.

The Kremlin has rejected accusations it was behind the sudden illness of the leading Russian opposition politician, one day after a highly anticipated German investigation concluded Navalny had been poisoned by a banned Soviet-produced military-grade nerve agent.

The investigation, whose findings were announced Wednesday by German Chancellor Angela Merkel, concluded Navalny was recovering in a Berlin hospital from Novichok, a Soviet-era toxin that Merkel said was clearly an attempt on the opposition politician's life by state-sponsored actors in Russia.

FILE - German Chancellor Angela Merkel speaks to media in Berlin, Germany, Sept. 2, 2020.

"Alexei Navalny was the victim of an attack with a chemical nerve agent of the Novichok group. This poison could be identified unequivocally in tests," said Merkel.

"There are serious questions that only the Russian government can answer."

The Kremlin immediately cast doubt about the diagnosis, maintaining that Russian doctors conducted analyses that showed no signs of the nerve agent — much less poisoning — before Navalny was evacuated to Berlin from a Siberian hospital on August 22.

"Before the patient was taken to Germany, in accordance with all international standards, a whole series of tests was done in Russia, and no poisonous substance was found," said Dmitry Peskov, the Kremlin's spokesman, reacting to Merkel's announcement.

"There are no grounds to accuse the Russian state. And we are not inclined to accept any accusations in this respect," added Peskov.

FILE - Police officers stand outside the Charite Mitte Hospital Complex, where Russian opposition leader Alexei Navalny is receiving medical treatment, in Berlin, Germany, Aug. 24, 2020.

Russia's Foreign Ministry also cast scorn on the report and said its ambassador to Germany had been summoned by German authorities but not presented with evidence.

"Where are the facts, where are the formulas, at least some kind of information?" asked the ministry spokeswoman, Maria Zakharova, in an interview on Russia's state-run Channel One.

On Friday, the head of Russia's Interior Ministry, Vladimir Kolokoltsev, argued that he saw no criminality to pursue in the incident. 

"Where would this criminal even be?" said Kolokoltsev in comments to the Interfax news agency.

The minister added, "We see no basis" to investigate.

Yet Navalny's chief strategist, Leonid Volkov, said the mere traces of Novichok established the direct complicity of the Russian leadership.

"Novichok means it was Putin. It's not something that you can pick up at the pharmacy," Volkov said in a Facebook post, referring to Russian President Vladimir Putin. 

Volkov compared the German discovery of the Soviet-made substance to leaving an autograph in blood at the scene of a crime.

International ramifications

The findings — and dueling realities — suggested Russia was headed for a repeat clash with Western powers similar to fallout after the attempted poisoning of former Russian spy Sergei Skripal and his daughter, Yulia, in Salisbury, England, in 2018.

Both the Skripals ultimately survived and British investigators concluded Novichok was "highly likely" behind the poisonings — a term widely mocked by Russia's Foreign Ministry and Kremlin state media as evidence of unsubstantiated and politically motivated accusations against Russia.

A British woman later died from accidental exposure to the substance.

FILE - Inspectors from the Organization for the Prohibition of Chemical Weapons (OPCW) arrive to begin work at the scene of a nerve agent attack on former Russian agent Sergei Skripal, Salisbury, Britain, March 21, 2018.

The Salisbury poisonings also triggered the expulsion of more than 100 Russian diplomats and additional sanctions by the United States, Britain and other Western allies — a specter that Merkel suggested may be in the offing once again.

The chancellor said she had notified EU and NATO partners about the German report and that allies would issue "an appropriate, joint reaction" to Russia.

The poisoning also echoed in the U.S. presidential race, with Democratic nominee Joe Biden accusing the Kremlin of an "outrageous and brazen attempt on Mr. Navalny's life" and President Donald Trump of failing to stand up to Putin.

Trump's secretary of state, Mike Pompeo, has previously expressed concern about Navalny's condition, and called for an investigation "if the reports prove accurate" about deliberate poisoning.

U.S. National Security Council spokesman John Ullyot said Wednesday, "The United States is deeply troubled by the results released today," calling Navalny's poisoning "completely reprehensible."

"We will work with allies and the international community to hold those in Russia accountable, wherever the evidence leads, and restrict funds for their malign activities," Ullyot added.

Meanwhile, the lower house of Russia's parliament is launching its own investigation into Navalny's illness — arguing the opposition leader was poisoned by Western security services in an effort to blacken Russia's reputation and, perhaps, derail a key German-Russian gas project. 

Trump has imposed sanctions on European companies that help Russia complete a key gas pipeline deal to Germany known as Nord Stream 2.

There were calls Thursday among German lawmakers to reconsider the deal.

Sudden illness 

Navalny fell ill August 20 during a flight to Moscow from Siberia — forcing the pilot to carry out an emergency landing in the city of Omsk.

Within hours, news broke that the opposition leader was in a coma in a local hospital fighting for his life.

FILE - An ambulance which is believed to transport Alexei Navalny arrives at the Charite hospital in Berlin, Germany, Aug.22, 2020.

Yet Russian doctors initially delayed Navalny's transfer for care to Berlin — arguing his condition was too fragile for travel, despite the wishes of his family.

Navalny's family and supporters argue the delays were intended to obscure what toxin had felled the opposition leader.

In the run-up to the German report, the Kremlin had been arguing there was no basis to even investigate what had caused Navalny's sudden illness.

He is currently receiving treatment at Berlin's Charite Hospital, where doctors say he remains gravely ill in an artificially induced coma.

Navalny has long been a problematic figure for the Kremlin — detailing corruption and excess at the highest levels of the government on his popular YouTube channel.

The channel's mix of investigative journalism and caustic humor has resonated with younger Russians in particular — and made scores of enemies in government and business circles.

Navalny also has made no secret of his political ambitions. He tried to run a campaign for president in 2018 that ultimately was undone by a lingering criminal conviction.

His supporters — and the European Court of Human Rights — said the charges were filed to keep him out of politics.

Despite Navalny's prominence as a leading Kremlin critic, government officials have an unofficial policy to never mention his name — a tradition the Kremlin spokesman continued even as he fielded questions about the opposition leader's poisoning.

"We're without a doubt interested in finding out the cause behind what happened," said Peskov, referring to Navalny merely as "the Berlin patient."

Isabela Cocoli contributed to this report.