Russia has rehearsed its ability to launch a “massive" nuclear strike in a drill overseen by Vladimir Putin, according to the Kremlin.
The military exercise on Wednesday evening involved delivering a “response to an enemy nuclear strike", Defence Minister Sergei Shoigu said.
State television showed Putin directing the exercise on a video call with top military officials.
While similar drills are held every autumn, Shoigu's pointed comments came amid soaring tensions between Russia and the West over the fighting in Ukraine.
The drill came hours after Russia’s upper house voted to rescind its ratification of a global nuclear test ban.
The bill to end ratification of the Comprehensive Nuclear Test Ban Treaty will now be sent to Putin for final approval.
Putin has said that revoking Russia's 2000 ratification would “mirror" the stance of the US, which signed but did not ratify the nuclear test ban.
The test ban treaty, adopted in 1996, bans all nuclear explosions anywhere in the world, but the treaty was never fully implemented.
Alongside the US, it is yet to be ratified by China, India, Pakistan, North Korea, Israel, Iran and Egypt.
There are widespread concerns that Russia could move to resume nuclear tests to try to discourage the West from continuing to offer military support to Ukraine.
Hawks within the Kremlin and in pro-Russian media have spoken in favour of a resumption of the tests.
Putin claims not to have yet formed an opinion on the issue.
Russia's Deputy Foreign Minister Sergei Ryabkov said earlier this month that Moscow will continue to respect the ban and will only resume nuclear tests if Washington does it first.
He said on Wednesday that the Russian Foreign Ministry had received US proposals to resume a dialogue on arms control issues, but said Moscow doesn't consider it possible over current tensions.
“We aren't ready for it because the return to a dialogue on strategic stability ... as it was conducted in the past is impossible until the US revises its deeply hostile policy course in relation to Russia,” he told reporters according to Russian news agencies.
