Trump sent letters to 14 countries threatening them with new tariffs, and the White House said more countries may be included in the coming days.

President Trump on Monday said the U.S will impose 25% tariffs on goods from South Korea and Japan by Aug. 1, while also threatening to hit a dozen other nations with steep import duties by next month.

The letters listed a range of tariffs. Goods entering the U.S. from Japan, South Korea, Malaysia, Kazakhstan, and Tunisia will be subject to a 25 percent levy. There will be a 30 percent levy on South African and Bosnian goods, while imports from Indonesia will be subject to a 32 percent rate.

President Donald Trump said Tuesday he’s imposing a new 50% tariff on all copper. However, it’s unclear when the new tariff would take effect.

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.

President Trump says he's not extending his latest deadline for higher tariffs beyond Aug. 1, when he's warned new countries will pay higher rates.

Stocks fell on Wall Street as the Trump administration stepped up pressure on trading partners to make deals before punishing tariffs imposed by the U.S. take effect. The S&P 500 lost 0.8% Monday.

CBS News MoneyWatch correspondent Kelly O'Grady reports on how markets are reacting after President Trump pushed back the deadline for countries to make trade deals with the United States. Countries now have until August 1 before they'll face tariff increases.