President Donald Trump vowed to push forward with his aggressive tariff regime in the coming days, stressing he would not offer additional extensions on country-specific levies set to now hit in early August while indicating he could announce substantial new rates on imports of copper and pharmaceuticals.

The Yale Budget Lab noted that the letters sent Monday would hike the effective tariff rate on U.S. consumers to the highest since 1934.

The leaders of Japan and South Korea were the first to get letters on Monday that informed them of the new tariff rates.

The president is again threatening higher tariff rates on a dozen foreign nations, as a deadline elapses this week for making trade deals.