Russian president Vladimir Putin has overseen a military exercise involving Russia's nuclear forces amid escalating tensions over Ukraine.
Putin said the exercise had been planned back in November.
He was speaking in televised remarks from the Defence Ministry's headquarters where he oversaw the exercise along with leaders of several ex-Soviet nations which are members of the Collective Security Treaty Organisation.
He said that the manoeuvres involved the military across the entire Russian territory, including the nation's nuclear forces.
Putin was quoted as saying that the exercises simulated dealing a massive retaliatory nuclear strike in response to an enemy attack - an unusually blunt statement that reflected tensions with the west over Ukraine.
As part of the manoeuvres, a Topol intercontinental ballistic missile launched from the Plesetsk launch pad in north-western Russia successfully hit a designated target on the Kura testing range on the far eastern Kamchatka peninsula, the military said.
Two nuclear submarines of the Northern and Pacific Fleets, the Tula and the Podolsk, also fired intercontinental ballistic missiles.