MOSCOW, Dec. 22 (Xinhua) -- Russia will respond in kind if the United States resumes nuclear testing, Russian Deputy Foreign Minister Sergei Ryabkov said Monday.

The minister noted that the United States has so far failed to respond to Russia's initiative to continue observing the core limits of the New Strategic Arms Reduction Treaty (New START) after its expiration.

In late September, Russian President Vladimir Putin said at a Security Council meeting that if the U.S. refrains from actions undermining the existing balance, Russia would continue to observe the core limits of the New START treaty for one year after its expiration.

Signed by Russia and the United States in 2010, the treaty imposes caps on the number of deployed nuclear warheads and strategic delivery systems. It remains the only active nuclear arms control agreement between the two nuclear superpowers. Moscow and Washington officially extended the treaty by five years in February 2021. Enditem