Trump re-positions 2 nuclear submarines after "foolish" statements by Russia's ex-president

U.S. President Donald Trump has ordered two U.S. nuclear submarines to be re-positioned in response to what he calls "foolish threats" from Russia's former president.

The escalation comes after a spat between Trump and Dmitry Medvedev, who currently serves as the deputy chairman of the Russian security council.

Vincent McAviney reports on the intensified back and forth as Trump's deadline for a ceasefire next week in Ukraine looms.