Russia on Thursday warned the United States of consequences if it moves to deploy land-based missiles in Europe in contravention of a key Cold-War era arms control treaty.
"It is clear that such actions would mean complete destruction by the American side of the regime of the treaty with all its attendant consequences," the Russian foreign ministry said, referring to the 1987 INF treaty on intermediate-range and shorter-range missiles.
"We urge the United States to ensure the full implementation of the INF, (and) not to threaten the feasibility of this document," the ministry said in a statement.
The two countries have accused each other of violating the treaty signed by US President Ronald Reagan and Soviet leader Mikhail Gorbachev in 1987.
US defence officials said last week Washington is considering a range of moves to counter Russia's alleged violation of the treaty, including bolstering missile defences or deploying land-based missiles in Europe.
The INF agreement eliminated nuclear and conventional ground-launched ballistic and cruise missiles with intermediate range of 500-5,500 kilometres (300-3,400 miles). The treaty marked the first time the superpowers had agreed to reduce their nuclear arsenals.
A US State Department report last week said Russia in 2014 "continued to be in violation of its obligations under the INF Treaty not to possess, produce, or flight-test a ground-launched cruise missile (GLCM) with a range capability of 500 kilometres to 5,500 kilometres, or to possess or produce launchers of such missiles."
The Russian foreign ministry said that statement was not "consistent with reality", challenging the United States to provide firm evidence.
Moscow for its part took issue with Washington's plans to deploy in Poland and Romania systems capable of launching Tomahawk cruise missiles.
"Such deployment would directly contravene the INF treaty," the foreign ministry said.
Ties between Russia and the United States sank to their post-Cold War lows after Moscow annexed Crimea from Ukraine last year and supported Russian-speaking rebels fighting Kiev government forces.