Russia has covertly deployed a new, fully operational cruise missile in an apparent violation of an arms control treaty, US officials have claimed.

Barack Obama wrote to President Vladimir Putin after Russia tested the missile in 2014, contending that the test violated the landmark 1897 accord that banned the US and Soviet Union from using intermediate and shorter-range missiles and helped bring the Cold War to a close.

The Russians appear to have disregarded the warning, and the missile has now been deployed according to the New York Times.