To help cushion the blow, the administration established a process that allows companies to apply for an exemption from the tariffs. Companies must demonstrate that the import cannot be obtained domestically. Some of those requests have been approved and administration officials have insisted the process is apolitical.

Apple products, which are largely assembled in China, have so far mostly evaded tariffs. Last year, the Trump administration told Apple’s chief, Tim Cook, that it would not place tariffs on iPhones, according to a person familiar with the talks who spoke on the condition of anonymity for fear of upsetting negotiations. It is unclear if the president’s thinking has changed.

Last week, Apple filed 15 requests with the United States trade representative to exclude certain products it imports from China from the tariffs. The requests covered a variety of imported components, like power cables and circuit boards, used in the Mac Pro desktop, a high-end computer that sells for around $6,000. In the requests, the company asserts it cannot acquire the products in the United States or other countries outside China.

“There are no other sources for this proprietary Apple-designed component,” the company wrote.

But Mr. Trump has shown little sympathy for American companies that insist they must manufacture or obtain their products abroad. He has blasted companies like Harley-Davidson that have shifted some production outside the United States and suggested that he will use tariffs on trading partners to force more manufacturing back to the United States. Last year, Mr. Trump placed tariffs on imports of steel and aluminum from Japan, Canada, Mexico and the European Union, saying that would lead to a resurgence of American metal manufacturing.