US president posted copies of letters addressed to leaders of both countries on social media

Donald Trump unveiled plans to step up his trade wars on Monday, announcing Japan and South Korea will soon face US tariffs of 25% in a significant escalation of his controversial economic strategy.

The US president, who indicated that he would notify as many as as 15 countries of new, higher rates on Monday, posted copies of letters addressed to the leaders of Japan and South Korea on social media. Trump said the rates are set to go into effect August 1.