Russia said on Wednesday that Washington's decision to stop sharing some data on its nuclear forces under the New START arms control treaty will not prompt Moscow to review its own decision to suspend its participation in the pact.
The United States announced on Tuesday it would stop exchanging some information on its nuclear forces after President Vladimir Putin ordered Moscow to suspend its own participation in February.
Russia said on Wednesday it would voluntarily stick to agreed limits on the number of nuclear warheads it can deploy regardless of the US step.
"We have voluntarily made commitments to adhere to the central quantitative limits set by that treaty," Deputy Foreign Minister Sergei Ryabkov was quoted as saying in an interview with the state RIA news agency.
"That's it. Our position does not depend on whether the Americans will or will not hand over their data to us," he said.
The US remained a party to the agreement and was still obliged to send data, he added.
"The US, unlike Russia, has not formally suspended the Treaty. Accordingly, they are obliged to comply with its provisions in full," Ryabkov said.
Putin justified Russia's suspension last month by saying, without providing evidence, that the West had been directly involved in Ukrainian attacks against bases for Russian strategic bomber planes deep inside Russian territory.
He said NATO demands that Russia should allow inspections of its nuclear bases under the New START treaty were therefore absurd.
Signed in 2010 and due to expire in 2026, the New START treaty caps the number of strategic nuclear warheads that both countries, the world's largest nuclear powers, can deploy.
Under its terms, Moscow and Washington may deploy no more than 1,550 strategic nuclear warheads and 700 land- and submarine-based missiles and bombers to deliver them.
Both the United States and Russia have said that a nuclear war can never be won and must never be fought. But the conflict in Ukraine has prompted Russia to repeatedly warn that it will use any weapon in its arsenal to defend itself if the very existence of the Russian state is threatened.
Russia's defence ministry said on Wednesday that it had begun exercises with its Yars intercontinental ballistic missile system and several thousand troops, in what is likely to be seen as another attempt by Moscow to show off its nuclear strength.