An exemption that allowed cheap Chinese goods to enter the United States duty free was eliminated on Friday, which could lead to higher prices and delays on purchases.

President Donald Trump has closed a tariff loophole that allowed Chinese e-commerce giants like Shein and Temu to sell low-cost goods in the U.S. without paying duties—a move that is expected to drive up prices for American consumers.

Trump referred to the commonly used trade exemption as a “big scam going on against our country, against really small businesses.”