Russia has reportedly violated an arms control treaty signed with the US by secretly deploying a new cruise missile.
The deployment of the ground-launched SSC-8 cruise missile was first reported by The New York Times.
Signed between the US and Russia in 1987, the Intermediate-Range Nuclear Forces (INF) treaty requires both countries to eliminate ground-launched ballistic and cruise missiles with ranges between 500km and 5,500km.
Under the agreed terms, the US and Russia must also destroy launchers and support equipment for these missiles within three years of the treaty being enforced.
Reuters quoted an anonymous White House official as saying: “We know that this is an old issue. The Russians have been building and testing these things in violation of the INF treaty going back to the Obama administration.
"The issue now is the things are deployed and it’s an even greater violation of the INF treaty.”
A Nato official was quoted by CNN as saying: "The INF Treaty eliminated an entire category of weapons that threatened Europe, in particular the threat of short-warning attacks.
"The treaty remains a key component of our security, and any Russian non-compliance is a serious concern for the alliance.
"Nato allies have the capabilities in place to ensure that Russia will not gain any military advantage from disregarding the INF Treaty.”
Missile development and testing have been carried out for several years, despite the US Government's efforts to convince Russia to correct the violation.