U.S. warns Putin of 'catastrophic' consequences over nuclear weapons
WASHINGTON, Sept 25 (Reuters) - 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, U.S. National Security Adviser Jake Sullivan said on Sunday.
Sullivan's remarks represented the latest American warning following the thinly veiled nuclear threat made by Vladimir Putin last Wednesday in a speech in which the Russian president also announced his country's first wartime military mobilization since World War Two.