President Vladimir Putin on Thursday signed a law withdrawing Russia's ratification of the global treaty banning nuclear weapons tests, a step condemned by the organisation which promotes adherence to the landmark arms control pact.

Moscow says its deratification of the Comprehensive Nuclear Test Ban Treaty (CTBT) is merely designed to bring Russia into line with the United States, which signed but never ratified the treaty. Russia will not resume nuclear testing unless Washington does, say Russian diplomats.

Nor, they say, will the move change the nuclear posture of Russia, which has the world’s largest nuclear arsenal, or the way it shares information about its nuclear activities as Moscow will remain a treaty signatory.