The Kremlin said on Wednesday that Russia was adjusting its nuclear doctrine because the United States and its Western allies were threatening Russia by escalating the war in Ukraine and riding roughshod over Moscow's legitimate security interests.

Russia, the world's biggest nuclear power, is making changes to its nuclear doctrine - which sets out the circumstances under which Moscow would use such weapons - due to the West's increasing support for Ukraine which Russia invaded in 2022.

Kremlin spokesman Dmitry Peskov, in Moscow's most detailed explanation to date, linked the move directly to the "threats" created by the West and blamed the United States for destroying the post-Cold War security architecture of Europe.

The West, Peskov said, had rejected dialogue with Russia and taken a line of attack against its security interests while stoking "the hot war in Ukraine."

"It is the United States that is the ringmaster of the process of provoking tension," Peskov said.

Peskov indicated that revision of the nuclear doctrine was at an early stage, saying that the current tensions would be analysed carefully and then form the basis of proposed changes.

Russia's current published nuclear doctrine, set out in a 2020 decree by President Vladimir Putin, says Russia may use nuclear weapons in case of a nuclear attack by an enemy or a conventional attack that threatens the existence of the state.

Russia and the United States are by far the world's biggest nuclear powers, holding about 88% of the world's nuclear weapons, according to the Federation of American Scientists, opens new tab. Both are modernising their nuclear arsenals while China is rapidly boosting its nuclear arsenal.

The war in Ukraine has triggered the biggest confrontation between Russia and the West since the 1962 Cuban Missile Crisis, with both sides saying they cannot afford to lose the conflict.