Apple and Google restored TikTok to their app stores in the United States on Thursday evening, several weeks after they removed the short-form video platform in compliance with a new law that banned it in the country.

President Trump tried to pause enforcement of the TikTok ban with an executive order, but the companies were reluctant to bring TikTok back until they were certain they were not breaking the law.

The law, signed last year, had called for ByteDance, TikTok’s Chinese parent company, to sell TikTok to a non-Chinese owner by Jan. 19. The law targeted app store operators and internet hosting companies with steep financial penalties if they distributed or maintained TikTok.

Mr. Trump’s executive order prompted confusion among technology companies. While Apple and Google kept TikTok out of their app stores, companies like Oracle, which provided back-end technology support for the app, resumed working with it after a brief shutdown in January.

While Apple and Google blocked new downloads of TikTok, the app was largely unaffected if it was already downloaded on American phones. TikTok claims 170 million U.S. users.

The return of the app to the stores is a positive sign for TikTok, which now has until early April to find a buyer. It’s also a remarkable turnabout for the company. Just a month ago, it was facing down a ban with wide bipartisan support in Congress. The law was upheld unanimously by the Supreme Court — only to be upended by Mr. Trump.

TikTok executives told video creators in a briefing call on Tuesday that it was optimistic that Apple and Google would soon reinstate the app, said H. Lee Justine, a TikTok creator and author, who was on the call.

“They said that the administration had given them a lot of information that they wouldn’t be penalized and that they were really hopeful that any day now they would put it back in the app stores,” she said in an interview. “It makes me very hopeful that they felt that they could do this because hopefully this means that long term there’s not going to be issues and this will work out.”

TikTok declined to comment on its return to the app stores or the briefing.

This is a developing story. Check back for updates.