Former Russian president Dmitry Medvedev has become embroiled in a tense back-and-forth on social media that prompted U.S. President Donald Trump to announce he had ordered the re-positioning of two U.

Former Russian president Dmitry Medvedev, who is currently serving as deputy chair of the security council of the Russian Federation, is embroiled in a social media spat with United States President Donald Trump,

Kremlin spokesman Dmitry Peskov downplayed the significance of Trump's remarks, made last Friday, in which Trump said he had ordered the deployment of two US nuclear submarines to "the appropriate regions" in response to statements by former Russian President Dmitry Medvedev regarding the risk of war between nuclear powers.