President Trump on Monday said the U.S will impose 25% tariffs on goods from South Korea and Japan by Aug. 1, while also threatening to hit a dozen other nations with steep import duties by next month.

The U.S.’s closest security allies in Asia, along with six Southeast Asian countries, have been given another three weeks to negotiate trade deals — or face higher tariffs.

President Donald Trump announced on Monday that he is levying tariffs against South Korea and Japan beginning in August. Trump