The US president said he's ordered two nuclear submarines to move closer to Russia, after a social media spat with Russia's ex-president.

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.

President Donald Trump said he's ordered two nuclear submarines to move in the "appropriate regions" in response to recent comments from Russia's Dmitry Medvedev.