The country’s new president, in office for a little over a month, had just dispatched his senior deputies to Washington to try to work out a trade deal.

While South Korean imports to the U.S. face 25% tariffs, the same as Trump promised in April, the rate on Japan has been raised by 1 percentage point to 25%.

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.

Secretary of State Marco Rubio met counterparts in Southeast Asia during his first visit to the region since taking office.

Trump said on Tuesday that South Korea should be paying for its own military protection, suggesting the US ally needed to pay more for the US troop presence there, a day after the tariff announcement.