Russia is testing the readiness of a missile unit that forms part of its strategic nuclear forces, the defence ministry has said – with Russian officials having repeatedly raised the spectre of nuclear war over the West’s support for Ukraine.

Russia is testing the combat readiness of a unit equipped with Yars intercontinental ballistic missiles in a region northwest of Moscow, news agencies quoted the defence ministry as saying on Friday.

This image shows a Yars intercontinental ballistic missile being test-fired as part of Russia's nuclear drills from a launch site in Plesetsk, northwestern Russia. (Photo: AP)

MOSCOW (Reuters) - Russian President Vladimir Putin said on Friday Russia would not let Ukraine get nuclear weapons, after Ukraine's leader said that since Kyiv had given up its Soviet-era nuclear arms, it must join NATO.

President Vladimir Putin repeatedly brandish the nuclear sword, reminding everyone that Russia has the world’s largest atomic arsenal.

Russian ruler Vladimir Putin has described as a provocation the speculation about Ukraine's possible creation of nuclear weapons and said that any step in this direction "will entail a corresponding reaction".