Russia argues it is Ukraine and the US which are preparing to trigger biological warfare through the use of chemical weapons.
Moscow’s foreign ministry said “radical Ukrainian groups under the control of the representatives of American special services” were plotting atrocities.
It said they were planning multiple attacks including “the destruction of containers with toxic chemicals in highly populated areas”.
“The objective of such actions is to accuse Russia of the use of chemical weapons against the civil population and violating its obligations,” it added.
Boris Johnson has raised concerns that disinformation is being sown by the Kremlin so it can deflect blame for its own atrocities.
“They start saying that there are chemical weapons that have been stored by their opponents or by the Americans,” the Prime Minister told Sky News.
“And so when they themselves deploy chemical weapons, as I fear they may, they have as a sort of a maskirovka, a fake story ready to go.”
US President Joe Biden vowed that Russia “would pay a severe price if it used chemical weapons” in Ukraine.
But speaking at the White House he ruled out any direct military invention as it would spark “World War Three”.
“We will not fight a war against Russia in Ukraine”, he told reporters.