Russia has insisted it will not use nuclear weapons in the Ukraine war, saying “there can be no winners in a nuclear war”.
Foreign ministry spokesperson Alexei Zaitsev also accused those who suggested Russia might launch a nuclear strike of "deliberate lies".
But it was Vladimir Putin himself who first propagated the spectre of nuclear war shortly after he launched the invasion of Ukraine in late February, putting Russia's nuclear forces on "special" alert following the West's so-called "unfriendly" response in the form of sanctions.
And Ukrainian president Volodymyr Zelensky pointed out on Friday that it’s the “72nd day of the fully-fledged war and we can see no end of it yet - and we cannot feel any willingness of the Russian side to end it”.
Zaitsev told reporters the use of nuclear weapons by Russia - a risk that Western officials have publicly discussed - was not applicable to what Moscow calls its "special military operation" in Ukraine.
"Russia firmly adheres to the principle that there can be no winners in a nuclear war, and it must not be unleashed," he said.
Russia is one of nine countries which has nuclear warheads: 4,477, which excludes 1,500 "retired" warheads.
The eight others are the US (5,428), China (350), France (290), UK (225), Pakistan (165), India (160), Israel (90) and North Korea (20).
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Between the Nato allies of the US, France and the UK, there are 5,943 nuclear warheads.
Zelensky, who was speaking to UK think tank Chatham House on Friday, said Russia believes it cannot be “made responsible for the war crimes because they have the power of the nuclear state”.
He added bridges with Russia are not yet “destroyed”, leaving the door open for future negotiations.
However, he said talks can only take place if Russia withdraws to his pre-invasion positions, as of 23 February, saying he was not elected to lead “a mini-Ukraine of some kind”.
Zelensky said arrangements were needed for discussions to “stop the killing”, with “diplomatic channels” used to regain Ukraine’s territories.
According to the United Nations’ Office of the High Commissioner for Human Rights, 3,309 civilians, including 234 children, have been killed and 3,493 people have been injured. However, it believes the actual numbers will be far higher.
Meanwhile, some 12 million people are thought to have fled their homes since the war began.