'A lot of people have questioned whether the bar for Russian nuclear use is as high as its official statements say,' says Olga Oliker with the International Crisis Group. But not everyone thinks its nuclear rules are so clear-cut.

Russia officially says it would use nuclear weapons only if the nation's very survival was at risk. Russia says it would use nuclear weapons only as a last resort, but some are skeptical Right now, there's no indication that the battlefield nukes have been pulled out of storage. 'It's like you could press the button, but then nothing happens, because the button is not connected to anything.' 'Normally, in peacetime, the command and control system is configured in a way that makes the transmission of an actual command very much impossible,' he says. One possibility, says Podvig, is that the order activated the nation's nuclear command and control system. It's unclear what a 'special mode of combat duty' actually is. 'He basically said, 'Because of all these hostile or aggressive statements and aggressive policies, we should start this special mode of combat duty of our deterrent forces,'' says Pavel Podvig, a senior researcher at the United Nations Institute for Disarmament Research in Geneva. In a brief clip, Putin is shown speaking to two stony-faced generals about the country's nuclear forces. The exact meaning of Putin's order remains unclear Some experts, though, are worried about the possibility of nuclear escalation. 'At this time we see no reason to change our own alert levels,' White House press secretary Jen Psaki told reporters on Monday.

said it would not respond with changes to its own nuclear posture.

Over the weekend, Russian President Vladimir Putin gave orders to his nation's nuclear forces. Russian Defense Ministry Press Service /AP Russia has the world's largest nuclear arsenal. A 2020 test of a ground-based intercontinental ballistic missile from the Plesetsk facility in northwestern Russia.

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