The U.S. Postal Service’s decision may block or delay parcels from retailers including Shein and Temu from entering the United States.

The original move could have made products from popular Chinese e-commerce sites such as Shein more expensive for Americans.

As part of a 10% tariff on Chinese imports, Trump also scrapped a rule that waived import duties on packages valued at under $800, which helped Temu and Shein.