Japan and South Korea, the United States’ closest security allies in Asia and key partners in its effort to counter China, were sent scrambling Tuesday after the U.S. president renewed his threat to impose steep tariffs on their goods,

In letters so far to 14 countries, including smaller exporters to the United States such as Serbia, Thailand and Tunisia, Trump hinted at opportunities for additional negotiations, even while warning that reprisals would draw a like-for-like response.

The U.S. will impose tariffs of 25% on Japan and South Korea beginning on Aug. 1, President Donald Trump announced on Monday in posts on Truth Social.