The US, France and UK on Sunday rejected a claim by Russia that Ukraine is preparing to use a "dirty bomb" on its own territory and pin the blame on Moscow, according to a joint statement.
The statement said the defense ministers of the three nations spoke with Russian Defense Minister Sergey Shoygu at his request, and they all rejected "Russia's transparently false allegations" that Kyiv will use the bomb as a provocation.
A dirty bomb or radiological dispersal device is a type of speculative radiological weapon that combines radioactive material with conventional explosives.
Shoygu raised the claim during his calls with his counterparts in several Western nations, including US Defense Secretary Lloyd Austin.
"The world would see through any attempt to use this allegation as a pretext for escalation. We further reject any pretext for escalation by Russia," said the statement.
The three nations also reiterated their "steadfast" support for Ukraine, saying "we remain committed to continue supporting Ukraine's efforts to defend its territory for as long as it takes.”
US Secretary of State Antony Blinken also held a phone call with Ukrainian Foreign Minister Dmytro Kuleba, during which the two diplomats discussed the Russian allegations.
Earlier, Austin spoke by phone for the second time this week with Shoygu, who the Pentagon said requested a follow-up call.
"Secretary Austin rejected any pretext for Russian escalation and reaffirmed the value of continued communication amid Russia’s unlawful and unjustified war against Ukraine," Pentagon Spokesman Brigadier General Pat Ryder said in a statement.