U.S. President Joe Biden issued a strong warning on Russia against using a dirty bomb or any other nuclear weapons in its war on Ukraine.
"Russia would be making an incredibly serious mistake for the use of tactical nuclear weapons," he said Tuesday when a reporter asked whether Russia is setting up a "false flag operation" – preparing to deploy dirty bomb as it accuses Ukraine of detonating it in its own territory.
"I'm not guaranteeing you that it's a false operation yet. I don't know. But it would be a serious, serious mistake," he said.
U.S. State Department spokesperson Ned Price said Tuesday there is reason for concern as Russia has "demonstrated a pattern of accusing others of that which it itself is ultimately planning." On Monday, Price warned of the "profound nature of consequences" should Moscow deploy such weapons.
Russia's ambassador to the United Nations, Vasily Nebenzya, sent a letter, seen by VOA, to U.N. Secretary-General Antonio Guterres and the Security Council late Monday, saying Russia "will regard the use of the dirty bomb by the Kyiv regime as an act of nuclear terrorism."
Ukraine has strongly denied Moscow's allegations that it is planning to detonate a dirty bomb on its own territory and has in turn accused Russia of plotting to use the threat of a bomb laced with nuclear material as a pretext for escalation in Ukraine.
The U.N. Security Council discussed the allegations at a closed-door meeting Tuesday.
"We've seen and heard no new evidence in this private meeting," Britain's deputy U.N. ambassador, James Kariuki, told reporters. "The ministers of the UK, France and the U.S. have been clear: this is transparently false allegations we are hearing from the Russian Federation. Ukraine has been clear; it has got nothing to hide; IAEA inspectors are on the way."
NATO Secretary-General Jens Stoltenberg said Monday that NATO allies rejected Russia's claims that Ukraine is preparing to use a dirty bomb on its own territory, adding, "Russia must not use it as a pretext for escalation."
Meanwhile, the head of Russia's nuclear, biological and chemical protection troops, Lieutenant General Igor Kirillov, in a media briefing, said Russian forces are "preparing to work under radioactive contamination."
International Atomic Energy Agency (IAEA) Director General Rafael Mariano Grossi confirmed that "no undeclared nuclear activities or material were found" in Ukrainian nuclear locations.
"The IAEA inspected one of these locations one month ago and all our findings were consistent with Ukraine's safeguards declarations," Grossi said.
Grossi confirmed that both locations are under IAEA safeguards and have been visited regularly by IAEA inspectors. He added that the IAEA received a written request Monday from Ukraine to send teams of inspectors to carry out verification activities at the two locations.
Russia has requested a second council meeting on Thursday to discuss its allegations that the United States and Ukraine have been conducting military biological activities on Ukrainian territory.
In a 310-page letter sent to the Security Council, president and the secretary-general, Russia's ambassador rehashes old claims about the two states planning to infect migratory birds, bats and even mosquitos with lethal pathogens and then deploy them to infect Russian troops and/or civilians.
Ambassador Nebenzia includes a draft resolution for the council to consider forming a commission to investigate U.S. and Ukrainian compliance with the Biological Weapons Convention. The commission would be made up of the 15 council members and be expected to report back by November 30. Such a proposal is unlikely to gain traction among council members.
Separately on Tuesday, European Commission President Ursula von der Leyen urged support Tuesday for the "fast rehabilitation" of Ukraine as it faces what she called targeted attacks by Russian forces on civilian infrastructure.
Speaking in Berlin at a conference to discuss the recovery and reconstruction of Ukraine, von der Leyen said Russia is clearly working to cut off Ukrainians from water, heat and electricity services as winter approaches. She said such Russian attacks "are pure acts of terror."
Von der Leyen described the scale of destruction in Ukraine eight months after Russia launched its invasion as "staggering."
"These are hard, scary and painful days for Ukrainians, but Ukrainians are showing us that they have hope and confidence in the future and they will keep fighting for it. And it is their future that brings us here today," she said.
The conference involves representatives from national governments, academic institutions and international organizations. The EU said the talks would cover how to prioritize Ukraine's needs and what options exist for financing projects.
No financial pledges or political agreements are expected.
Ukraine's government, along with the European Commission and the World Bank, estimated in a September report that it could cost $350 billion to rebuild the country after Russia's invasion.
The World Bank on Monday disbursed $500 million, supported by loan guarantees from Britain to Ukraine to help the government maintain essential services.
"The Russian invasion continues to cause massive destruction of Ukraine's infrastructure — including water, sanitation, and electricity networks — just as winter is approaching, further endangering Ukrainian people," World Bank Group President David Malpass said in a statement.
Ukrainian Foreign Minister Dmytro Kuleba and U.S. Secretary of State Antony Blinken spoke Monday about meeting Ukraine's needs for military aid, according to statements from both sides.
VOA's U.N. Correspondent Margaret Besheer and White House Bureau Chief Patsy Widakuswara contributed to this article. Some information for this story came from The Associated Press, Agence France-Presse and Reuters.