President Donald Trump dug in on his threat to impose a 50% tariff on the European Union and said a potential 25% charge on imported Apple Inc. smartphones would also apply to Samsung Corp. devices if they do not move production to the US.

Markets on Wall Street and in Europe declined rapidly in the morning after President Donald Trump posted a pair of tariff threats on social media, one aimed at Apple and the other at the European Union.

U.S. and European stocks dropped Friday after President Trump threatened to slap 50% tariffs on the European Union and 25% tariffs on Apple. Also, Russia's defense ministry said it has conducted a prisoner swap with Ukraine.