President Donald Trump approved tariffs on about $50 billion of Chinese goods, people familiar with the decision said, as the U.S. ratchets up its trade fight with Beijing over China’s alleged pressure on U.S. firms to transfer technology to Chinese partners.

The approval followed a 90-minute meeting on Thursday of senior White House officials, national-security officials and senior representatives of the Treasury, Commerce Department, U.S. Trade Representative’s Office.

It wasn’t clear when the tariffs would go into effect. Beijing has said that it intends to assess tariffs on a corresponding amount of U.S. goods.

USTR expects to announce the goods subject to tariffs on Friday and publish them in the Federal Register next week, the people familiar with the matter said. The affected imports would face 25% tariffs; the products are expected to be similar to those on a preliminary list that USTR released in early April.

The office has held public hearings on the list of 1,300 categories of products to see whether duties on any of the goods it selected would unduly harm U.S. consumers and businesses. USTR is expected to cut some of the products from the list and add others, especially high-tech items, the people familiar with the matter said.

The U.S. decision could become the start of a tit-for-tat series of retaliatory moves. If the U.S. hits China with tariffs, China will immediately retaliate with tariffs, said a Chinese official. “We hate unilateral actions,” the official said.

Beijing has already said it had prepared its own $50 billion list of U.S. goods that it would subject to tariffs, especially aircraft and soybeans.

After Beijing made that threat, President Trump upped the ante and said the U.S. would add another $100 billion of goods to the U.S.’s tariff list. The U.S. hasn’t followed up on that threat by enumerating what goods would be included in that batch.

On Thursday, Chinese Foreign Minister Wang Yi said China and the U.S. faced a choice between cooperation and mutual benefit on the one side and confrontation and mutual loss on the other.

“China chooses the first,” Mr. Wang told a joint news conference, after talks with U.S. Secretary of State Mike Pompeo in Beijing.

“We hope the U.S. side can also make the same wise choice,” Mr. Wang said. “Of course, we have also made preparations to respond to the second kind of choice.”

As word filtered through Washington that Mr. Trump was about to make a decision on tariffs, some trade hawks offered qualified support for the president. Rep. Rosa DeLauro (D., Conn.), a longtime opponent of free-trade deals, said “tariffs must be seen as one tool among many our country can use to hold bad actors like China accountable and to bring the Chinese government to the table to secure a more favorable balance of trade.”

But Ms. DeLauro added that Mr. Trump must come up with a “comprehensive strategy” for dealing with Beijing.

The conservative Tax Foundation calculated that the tariffs on Chinese imports, coming on top of U.S. tariffs on steel and aluminum exports, would lower “long-run” gross domestic product and wages by 0.06%, reduce employment by 45,293 positions and make U.S. taxes less progressive.