Russia's use of nuclear weapons in Ukraine, in response to Ukraine's alleged use of a "dirty bomb," would be a "very grave error," according to US President Joe Biden.

After receiving an updated coronavirus booster shot, Biden stated at the White House that the use of tactical nuclear weapons by Russia would be an extremely grave error.

"I cannot yet verify that it is a false flag operation. I'm not sure. But it would be a grave, grave error "he added.

In response to a question regarding whether Russian assertions that Ukraine was preparing a "dirty bomb" strike on its land were the beginning of a false-flag operation for Russia, the official stated that the allegations were not.

Ned Price, a spokesman for the U.S. Department of State, stated on Monday that Russia would face grave consequences if it used a "dirty bomb" or nuclear weapon against Ukraine.

Price stated that if Russia were to use an improvised nuclear bomb against Ukraine, "it would be another another evidence of Vladimir Putin's savagery."

Price told reporters, "If he were to use a so-called 'dirty bomb,' there would be consequences for Russia, regardless of whether it used a dirty bomb or a nuclear bomb." He did not outline the types of responses being considered by the United States.

A dirty bomb is a combination of conventional explosives and radioactive elements that, upon detonation, spread over a large region.

Russia has accused Ukraine of preparing to use such a device, which the West has rejected as a possible pretext for the Kremlin to employ a dirty bomb.

Sunday, the United States, France, and the United Kingdom categorically rejected the claim, stating in a joint statement that each of their defense ministers "made clear" in separate telephone conversations with Russian Defense Minister Sergey Shoygu "that we all reject Russia's transparently false allegations that Ukraine is planning to use a dirty bomb on its own territory."

"Any attempt to exploit this claim as a pretext for escalation would fall flat in the eyes of the international community. We further deny any justification for Russia's escalation, "they claimed,