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.

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%.

President Donald Trump said tariffs he plans to impose on South Korea are intended to “even out” what he described as an imbalance between trade and the cost of stationing U.S. troops in the country.