By Phil Stewart, Jonathan Landay and Ryan Patrick Jones WASHINGTON (Reuters) -U.S. President Donald Trump on Friday said he had ordered two nuclear submarines to be positioned in "the appropriate regions" in response to remarks from former Russian President Dmitry Medvedev about the risk of war between the nuclear-armed adversaries.

In a social media post, the president described the move as a deterrent prompted by threats by a former Russian leader. It is unclear if any submarines did actually change position.

The US president has exchanged barbs with Russian leader Dmitry Medvedev, who warned of ‘how dangerous’ Russia can be.