The United States Postal Service announced Tuesday that it had temporarily stopped accepting packages from China and Hong Kong, hours after an order by President Trump took effect that ended duty-free handling of many of these parcels.
The United States imports about three million parcels a day with little customs inspection and no duties collected — with most of them coming from China. An executive order that Mr. Trump signed on Saturday required that, starting Tuesday morning, each parcel must include detailed information on the contents and the tariff code that applies, as well as payment of those tariffs.
The provision on low-value parcels, known as the de minimis rule, was included in a broader order by Mr. Trump that imposed an extra 10 percent tariff on all imports from China.
But low-value parcels from China, which previously were tariff-free, now face not only the 10 percent tariff but also the many complex tariffs on every category of goods that these shipments previously skirted entirely.
A spokeswoman for the U.S. Postal Service did not respond to a question about whether stoppages were related to the change in trade rules, but only said that service would be temporarily suspended on inbound parcels from China and Hong Kong until further notice.
Customs and Border Protection did not immediately respond to a request for comment. The White House did not immediately provide comment.
Mr. Trump’s executive order imposed a 10 percent tariff on all Chinese imports starting Tuesday. The administration also ended the de minimis rule for China, arguing that the trade provision had become a conduit for fentanyl to be brought into the United States.
The Trump administration and other critics of de minimis argued that drugs and the precursors used to make them could be more easily shipped into the United States using the trade provision, since exporters who use de minimis do not have to provide as much information to U.S. Customs and Border Protection as they otherwise would.
The rapid rollout of Mr. Trump’s trade orders left little time for postal and customs officials to prepare to scrutinize so many packages. Mr. Trump said on Jan. 22 that he would put tariffs on Canada and Mexico on Feb. 1, then added China to the list on Jan. 23. He signed the executive orders Feb. 1, to take effect just three days later.
Supporters of de minimis have long said that eliminating the provision would increase the burden on U.S. customs officials. U.S. Customs and Border Protection is also the primary agency responsible for carrying out much of Mr. Trump’s enforcement actions at the border.
In an online event in October, Ralph Carter, the vice president of regulatory affairs at FedEx, observed that resources were stretched for U.S. customs officials and that a change to de minimis rules could lead to bottlenecks for shippers.
“If we convert these millions of shipments from de minimis into formal, informal clearances, we’re going to have serious supply chain backups, because there simply isn’t the resources to manage that,” he said. “And so that’s going to affect all importers, not just importers of de minimis.”
FedEx and UPS move a large portion of de minimis parcels, running frequent cargo flights from China to the United States to carry them. Neither company has responded yet to questions about how they will handle the new rules.
Shein and Temu are two of the largest e-commerce companies that connect low-cost Chinese factories to millions of American households. Shein declined on Tuesday to comment on the new rules on small packages, while Temu has not yet responded to questions sent on Monday.
The rapid expansion of e-commerce has posed a dilemma for the United States customs agency, Customs and Border Protection. Customs officials were already starting to be overwhelmed by small e-commerce parcels in 2016, when they persuaded Congress and the Obama administration to raise the minimum value for customs inspection and tariff collection to $800, from $200.
Raising the duty-free minimum has allowed millions of American households to buy very low-cost goods from China. But American manufacturers in sectors like textiles and apparel have contended that the imports of small parcels have undermined their ability to stay in business.
The number of duty-free parcels has risen tenfold since 2016. Congress has been debating for the past year how to change the rule on duty-free parcels. Mr. Trump has contended that allowing so many packages into the United States with little or no inspection has created a conduit for fentanyl, a synthetic opioid, and related supplies to enter the United States.
Jordyn Holman contributed reporting from New York.