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.