White House National Security Advisor Jake Sullivan said on Sunday that the U.S. and its allies are prepared to impose "severe consequences" on Russia if it deploys chemical weapons in Ukraine amid international concerns Moscow may be setting a pretext to launch such weapons.

Appearing on NBC's "Meet the Press," Sullivan declined to publicly detail the specific consequences that Russia would face if it uses chemical or biological weapons in Ukraine.

"I will just say that the United States, in coordination with our allies and partners, is prepared to impose such severe consequences," Sullivan said. "And we have communicated that directly to the Russians. We've consulted with our allies and partners about it. And we are prepared for that eventuality."

Since last week Russia has pushed a baseless claim that the U.S. and Ukraine are developing biological or chemical weapons. The U.S. State Department has called these claims "outright lies" and "total nonsense."

"When Russia starts accusing other countries of potentially doing something, it's a good tell that they may be on the cusp of doing it themselves," Sullivan said on Sunday.

Sullivan said the U.S. would seek to prevent Russia from deploying a false-flag operation by making it clear that any chemical weapons use in Ukraine will be coming from Russia.

Pentagon Press Secretary John Kirby said earlier on Sunday that there is currently no indication of an imminent chemical attack from Russia.

"We continue to watch this very very closely. It is of the Russian playbook that that which they accuse you of, they're planning to do now," Kirby said. "Again, we haven't seen anything [that] indicates some sort of imminent chemical biological attack right now, but we're watching this very very closely."