President Donald Trump cranked up the pressure on two of America’s key trading partners, Japan and South Korea, firing off letters Monday to the heads of their countries that informed them of their new tariff rate.

P resident Donald Trump shared letters Monday informing governments in Japan and South Korea that he’s levying 25% tariffs on their imports to the U.S., the first in an anticipated slew of tariff notices the administration is expected to send out before its self-imposed tariff pause ends Wednesday—though the letter suggests the rates could still change again.