U.S. media are reporting that Russia has deployed a new cruise missile that the United States contends is in violation of an arms control treaty.
The AP news agency and The New York Times said Moscow has secretly deployed a ground-launched cruise missile that contravenes the 1987 Intermediate-Range Nuclear Forces Treaty in southwest Russia.
The Times said Russia has two battalions of the missiles, which became operational late last year.
The Obama administration previously accused Russia of violating the treaty by testing the missile. The treaty bans ballistic missiles with a range of between 500 and 5,500 kilometers.
But Russian President Vladimir Putin has defended the missile program, arguing that the United States is also in breach of the treaty and new missiles are needed to maintain the balance of power..
The alleged treaty violation may arise when U.S. Defense Secretary Jim Mattis attends his first NATO meeting in Brussels on February 15.
The deployment has stirred concern in Congress, where Senate Armed Services Committee Chairman John McCain called it a "significant military threat to U.S. forces in Europe and our NATO allies."
McCain said the timing of the deployment suggests Putin is "testing" President Donald Trump.