In a statement, a State Department spokesperson said "Russia's refusal to facilitate inspection activities prevents the United States from exercising important rights under the treaty and threatens the viability of U.S.-Russian nuclear arms control."

The spokesperson added that Russia had a "clear path" for returning to compliance by allowing inspection activities, and that Washington remains ready to work with Russia to fully implement the treaty.

Talks between Moscow and Washington on resuming inspections under the New START nuclear arms reduction treaty were due to take place in November in Egypt, but Russia postponed them and neither side has set a new date for a meeting.

(Reporting by Humeyra Pamuk; writing by Rami Ayyub)