President Donald Trump on Monday warned countries against backing away from recently negotiated trade deals with the U.S. after the Supreme Court struck down his emergency tariffs, saying that he would hit them with much higher duties under different trade laws.

Trump, in a series of social media posts, said he also may impose license fees on trading partners as uncertainty over his next tariff moves gripped the global economy and sent stocks lower.

“Any Country that wants to ‘play games’ with the ridiculous supreme court decision, especially those that have ‘Ripped Off’ the U.S.A. for years, and even decades, will be met with a much higher Tariff, and worse, than that which they just recently agreed to. BUYER BEWARE!!!” Trump wrote on Truth Social.

Trump said that despite the court’s decision to invalidate his tariffs under the International Emergency Economic Powers Act, its decision affirmed his ability to use tariffs under other legal authorities “in a much more powerful and obnoxious way, with legal certainty, than the Tariffs as initially used.”

He suggested that the U.S. could impose new license fees on trading partners, but did not provide any details.

A spokesperson for the U.S. Trade Representative’s office did not immediately respond to a request for further comment on Trump’s plans.

In Brussels, the European Parliament decided on Monday to postpone a vote on the European Union’s trade deal with the U.S. after Trump imposed a new temporary import duty of 15% on imports from all countries.

EU goods under the deal would face a 15% U.S. tariff 15% U.S. tariff, with exemptions for hundreds of food items, aircraft parts, critical minerals, pharmaceutical ingredients and other goods, while the EU would remove duties on many imports from the U.S., including industrial goods.

Trump on Friday initially announced the temporary duty under Section 122 of the Trade Act of 1974 at 10%, but raised it to 15%, the maximum allowed under the statute, on Saturday.

The new duty is set to take effect at 12:01 a.m. EST (0501 GMT) on Tuesday. At that same moment, the U.S. Customs and Border Protection agency said it would stop collecting the now-illegal IEEPA duties, more than three days after the Supreme Court’s ruling.

Uncertainty Unnerves Markets

Wall Street stocks fell in early trade on Monday, as renewed tariff uncertainty in the wake of the Supreme Court ruling unnerved investors. The Dow Jones Industrial Average fell 1.34%, The S&P 500 fell 0.65%, while the tech-heavy Nasdaq Composite also was down 0.65% in mid-morning trade.

The U.S. dollar index fell 0.2% against major currencies.

The path forward for Trump’s foreign trade deals remained uncertain, with China urging Washington to scrap tariff measures, the EU freeze on its approval and India delaying planned talks.

U.S. Trade Representative Jamieson Greer said over the weekend that the Trump administration expected to open new Section 301 unfair trade practices investigations on several countries, a legal step expected to allow it to threaten new tariffs.

Trump used his social media post to again lash out against the justices who ruled against him, which included two who he had appointed during his first term in the White House. In its ruling, authored by conservative Chief Justice John Roberts, the court reasserted its power to check the power of the president.

The president also expressed concern that the top court could rule against his administration’s bid to restrict birthright citizenship in its forthcoming decision in that case.

—

(Reporting by Susan Heavey, David Lawder and Doina Chiacu, writing by David Lawder; Editing by Doina Chiacu, William Maclean and Nick Zieminski)