Vladimir Putin has put Russia’s nuclear deterrent forces on high alert amid tensions with the West over his invasion of Ukraine.
The Russian president told state TV that leading Nato powers had made “aggressive statements” on imposing hard-hitting financial sanctions against Russia and himself.
He ordered the Russian defence minister and the chief of the military’s general staff to put the nuclear deterrent forces in a “special regime of combat duty”.
The US ambassador to the United Nations said Putin’s order shows he is “escalating conflict in a manner that is unacceptable”.
Putin has previously warned foreign countries not to interfere in his invasion, saying it could lead to “consequences they have never seen”.
He has positioned anti-air missiles and other advanced missile systems in Belarus and deployed his fleet to the Black Sea in an effort to prevent a western intervention in Ukraine.
It comes after UK foreign secretary Liz Truss warned that Putin may be prepared to use the “most unsavoury means” to secure victory.
She said any use of nuclear or chemical weapons would represent an “extremely serious escalation” of the conflict which could see Russian leaders brought before the International Criminal Court.
Her warning came after the Commons Defence Committee chairman Tobias Ellwood said that in the “worst-case scenario” Putin could deploy low yield tactical nuclear weapons if his forces failed to make a breakthrough.
With the Russian advance on the capital, Kyiv, apparently bogged down in the face of fierce Ukrainian resistance, Truss said the survival of Putin’s regime could now be at stake if his invasion plan failed.
“This could well be the beginning of the end for Putin. I fear that he is prepared to use the most unsavoury means in this war,” she told Sky News’s Trevor Phillips on Sunday programme.
Asked about Russia’s arsenal of chemical and tactical nuclear weapons, she said: “I fear this conflict could be very, very bloody.