President Donald Trump on Monday informed Japan and South Korea that 25% tariffs will be imposed starting Aug. 1 on goods sent to the United States.

President Donald Trump said he’ll impose tariffs of 25% on goods from Japan and South Korea beginning Aug. 1, giving the two export powers a narrow three-week window to open their markets to American products and manufacture more in the US to avoid his unilateral levies.

The tariffs on two of America’s closest allies would go into effect Aug. 1, unless the countries reach some kind of trade agreement with the United States.