Ukrainian TV stations have been broadcasting messages explaining what to do in the event of a chemical weapons attack — a horrific prospect in an already gruesome war, but one that may also be unlikely.

U.S. President Joe Biden has said there are "real concerns” that Russia might resort to using the internationally banned munitions, as it looks to move past its struggles on the ground in its invasion of Ukraine. European nations have expressed similar worries, saying they wouldn’t put it past Russian President Vladimir Putin to do so.

"I don’t really expect it to happen. I mean why? What would be the use of chemical weapons?,” Michael Kofman, a specialist on the Russian military at CNA, a Washington think tank, said on a podcast Sunday. With little to gain militarily, he said, there would be enormous potential downsides.