Ukrainian troops reported on Saturday that Russian forces are deploying white phosphorus against them near the eastern city of Avdiivka, The Guardian reported.
While these reports cannot be confirmed, Ukrainian President Volodymyr Zelenskyy told NATO leaders earlier this week that Russia had used phosphorus bombs that had killed adults and children.
US President Joe Biden recently said that Russian President Vladimir Putin is considering using biological and chemical weapons against Ukraine.
Putin's "back is against the wall and now he's talking about new false flags he's setting up including, asserting that we in America have biological as well as chemical weapons in Europe, simply not true," Biden said.
"They are also suggesting that Ukraine has biological and chemical weapons in Ukraine. That's a clear sign he's considering using both of those," he added.
Biden’s comments came after Russia claimed that Ukraine is running chemical and biological labs with US support.
White House press secretary Jen Psaki later rejected the claims from Russia as "false" and "preposterous," and warned they could serve as a pretext for the Russians to deploy chemical weapons in their assault on Ukraine.
"It’s the kind of disinformation operation we’ve seen repeatedly from the Russians over the years in Ukraine and in other countries, which have been debunked, and an example of the types of false pretexts we have been warning the Russians would invent," Psaki said.
"Also, Russia has a track record of accusing the West of the very violations that Russia itself is perpetrating. In December, Russia falsely accused the US of deploying contractors with chemical weapons in Ukraine," she continued.
Zelenskyy also insisted that no chemical weapons or other weapons of mass destruction were developed in his country.
"No chemical or any other weapons of mass destruction were developed on my land. The whole world knows that. You know that. And if Russia do something like that against us, it will get the most severe sanctions response," he said.