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.

Trump sent letters to 14 countries threatening them with new tariffs, and the White House said more countries may be included in the coming days.

Dozens of America’s trading partners are bracing themselves for August 1, the new deadline for punishing tariffs on goods they export to the United States.