The Kremlin has tried to calm tensions in a feud between Trump and Medvedev that spiraled into nuclear threats.

President Donald Trump has reportedly hinted that his nuclear submarines are now "in the region of Russia" after he ordered them there following a comment made by former Russian President Dmitry Medvedev.

In the West, Dmitry Medvedev was once seen as a democrat who could liberalise Russia. In a stunning fall, he has been reduced to a rabid attack dog for Vladimir Putin who threatens Western capitals with nuclear weapons and launches into xenophobic rants on social media.