Jake Sullivan, a national security adviser, called Russia on Sunday to say that the United States and Ukraine are using nuclear weapons.

Sullivan said on CNN's State of the Union Sunday that it was a legitimate concern that Russia would use chemical weapons in Ukraine.

The United States and Ukrainians are accused of using chemical and biological weapons. Sullivan said that they themselves may be preparing to do so, and then trying to blame someone else.

—CNN (@CNN) March 13, 2022

He said that it was a classic page from the Russian playbook.

Ukrainian President Volodymyr Zelenskyy characterized Russian President Vladimir Putin's threat to use nuclear weapons in the Ukraine-Russia conflict as a bluff.

It is one thing to be a murderer. Zelenskyy said it was another to commit suicide.

Putin placed Russia's nuclear deterrent forces on high alert, which attracted the attention of the NATO. NATO Secretary General Jens Stoltenberg said the order is dangerous rhetoric.

Sullivan said on Sunday that Russia would pay a heavy price if it used chemical weapons. He said the US is communicating with its NATO allies and partners to reinforce the message.

We are watching this very closely. He said that the American president, Joe Biden, has to take that responsibility very seriously.

He said that when there is a nuclear power fighting in a conflict zone in Europe near NATO territory, we have to be concerned about the risk of escalation.

He said that they have not seen anything that would require them to change their nuclear posture.

Sullivan said that Putin is resorting to using nuclear weapons because his forces are not moving.