Donald Trump has now said two U.S. nuclear submarines are "where they have to be" — days after ordering their deployment following a fiery online spat with former Russian President Dmitry Medvedev. “A threat was made by a former president of Russia,

Russia urged caution after Trump claimed he redeployed nuclear subs in response to provocative remarks by a senior Russian official.

President Donald Trump issued a rare threat of nuclear escalation on Friday, saying he had ordered two nuclear submarines to be strategically positioned near Russia in response to what he said were aggressive remarks by Dmitry Medvedev,