U.S. and Ukrainian officials have struck down claims by Moscow that Ukraine is planning to use a “dirty bomb,” calling them “transparently false.”

The allegation was made by Russian Defense Minister Sergei Shoigu in a round of high-level calls with Western defense directors. Shoigu expressed “concerns about possible provocations by Ukraine with the use of a ‘dirty bomb’,” according to Russia’s defense ministry.

A “dirty bomb” is made to contaminate a large area with radioactivity, making it harmful or uninhabitable for residents there, without using a nuclear explosion.

Secretary of State Antony Blinken told his Ukrainian counterpart Dmytro Kuleba that “the United States rejects Russian Defense Minister Shoygu’s transparently false allegations that Ukraine is preparing to use a dirty bomb on its own territory and that the world would see through any attempt by Russia to use this allegation as a pretext for escalation,” according to a White House statement.

Ukrainian President Volodymyr Zelenskyy also slammed the Russian accusation.

“If Russia calls and says that Ukraine is allegedly preparing something, it means one thing: Russia has already prepared all this,” Zelenskyy said in his nightly address.

France’s Macron says terms of peace with Russia must be decided by Ukraine

French President Emmanuel Macron said that the terms of peace with Moscow must be decided by Ukraine, stressing that the war’s end “can’t be the consecration of the law of the strongest.”

“To stay neutral would mean accepting the world order of the strongest, and I don’t agree with this,” Macron said from Rome on Sunday, as the three-day Cry for Peace conference began.

Macron added that the international community would be receptive when Ukraine’s government decides on that time.

Ukrainian forces are gradually retaking territory occupied and illegally annexed by Russia, and while Moscow increasingly looks to be on the back foot, its ability to wreak havoc on Ukraine’s cities and vital infrastructure remains intact and analysts fear it could use more extreme measures in retaliation, such as nuclear weapons.

More than 1 million Ukrainian homes are without power

Russian strikes on critical energy infrastructure in Ukraine have left more than 1 million homes in the country without power, deputy head of the Ukrainian presidency Kyrylo Tymoshenko said over the weekend. Cities and towns all over Ukraine have faced power outages this month due to Russian attacks, prompting fear about what could be in store for the coming winter.

Ukrainian President Volodymyr Zelenskyy urged his fellow citizens to be careful with their power use.

“We should consume electricity very consciously. Please remember to limit the use of unnecessary and energy-consuming appliances ... It is necessary to be really frugal with energy consumption in public space,” he said in his nightly address Sunday.