US National Security Adviser Jake Sullivan warned on Sunday that the United States would respond decisively to any Russian use of nuclear weapons against Ukraine and has spelled out to Moscow the "catastrophic consequences" it would face.

"If Russia crosses this line, there will be catastrophic consequences for Russia. The United States will respond decisively," Sullivan told NBC's "Meet the Press" program, as quoted by Reuters.

(Israel National News' North American desk is keeping you updated until the start of Rosh Hashanah in New York. The time posted automatically on all Israel National News articles, however, is Israeli time.)

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