TikTok thanked President-elect Donald Trump on Sunday for promising to suspend a ban on the Chinese-owned social media platform, as it began restoring service to millions of U.S. users who had been bereft of the popular app for several hours.

“In agreement with our service providers, TikTok is in the process of restoring service. We thank President Trump for providing the necessary clarity and assurance to our service providers that they will face no penalties providing TikTok to over 170 million Americans and allowing over 7 million small businesses to thrive,” the social media website said in a statement.

“It’s a strong stand for the First Amendment and against arbitrary censorship. We will work with President Trump on a long-term solution that keeps TikTok in the United States,” TikTok said.

The short-lived shutdown came in accordance with a law passed last year with significant bipartisan congressional support requiring TikTok to be sold or shut down by Sunday to allay concerns about platform owner ByteDance’s presumed ties to China’s communist government.

The Supreme Court on Friday upheld that law, shooting down First Amendment claims by the firm and some of its users.

But Mr. Trump, who takes office at noon on Monday, said he would issue an executive order to suspend enforcement of the law. That left a murky period between the law’s Jan. 19 deadline and the inauguration, which led to Sunday’s shutdown and restoration — after Mr. Trump weighed in on his social media platform.

“I’m asking companies not to let TikTok stay dark!” Mr. Trump posted on Truth Social. “I will issue an executive order on Monday to extend the period of time before the law’s prohibitions take effect, so that we can make a deal to protect our national security. The order will also confirm that there will be no liability for any company that helped keep TikTok from going dark before my order.”

Google and Apple had removed TikTok from their app stores before the ban took effect on Sunday. Eight other applications owned by Bytedance also were removed.

Bytedance’s ownership scares many intelligence officials and the majority in Congress, where lawmakers said they feared the app would be used to scoop up and share with Chinese agencies data on U.S.-based users. Intelligence officials worry about the possibility of blackmail and other nefarious acts.

Congress also said TikTok could be used by Beijing to promote pro-Chinese or anti-American propaganda by shaping the types of content users see.

The ban, signed by President Biden, required ByteDance to divest TikTok by Jan. 19. It allowed for the president to delay that deadline. Mr. Biden had been reluctant to take a stand and instead indicated he was leaving the mess for Mr. Trump to deal with.

House Speaker Mike Johnson, Louisiana Republican, said Sunday he was happy to see the platform go dark in accordance with the law, but also said he expects Mr. Trump to strike a new deal.

“There needs to be a sale of full divestiture from the Chinese Communist Party, and I think President Trump is the one who can make that deal happen, so we’re excited about it,” Mr. Johnson told NBC’s “Meet the Press.”

Mr. Trump said he would “extend the period of time before the law’s prohibitions take effect” and not hold a company liable for carrying the application.

“Americans deserve to see our exciting Inauguration on Monday, as well as other events and conversations,” Mr. Trump posted on Truth Social.

He indicated he would like to see the U.S. have a 50% ownership with whoever purchases the company. Although Bytedance has received a $20 billion offer, there has been no deal closed.

TikTok CEO Shou Chew will attend Mr. Trump’s inauguration on Monday, and has thanked Mr. Trump for committing to help restore the application.

“We are grateful and pleased to have the support of a president who truly understands our platform. One who has used talk to express his own thoughts and perspectives, connecting with the world and generating more than 60 billion views of his content in the process,” Mr. Chew said.

TikTok had argued the law requiring divestiture violated its rights to free speech and association.

But the Supreme Court, in a unanimous ruling, said Congress was within its powers, particularly in an area of such importance to national security.

“There is no doubt that, for more than 170 million Americans, TikTok offers a distinctive and expansive outlet for expression, means of engagement, and source of community. But Congress has determined that divestiture is necessary to address its well-supported national security concerns regarding TikTok’s data collection practices and relationship with a foreign adversary,” the court said in an unsigned opinion.

In their ruling, the justices said the government “had good reason” to target TikTok specifically, given the national security concerns about Chinese ownership. The justices also said the law did not discriminate on TikTok’s content.

“Data collection and analysis is a common practice in this digital age. But TikTok’s scale and susceptibility to foreign adversary control, together with the vast swaths of sensitive data the platform collects, justify differential treatment to address the Government’s national security concerns,” the opinion read.

Mr. Biden’s administration defended the law.

Mr. Trump had urged the justices to delay the law, giving him a chance to trigger the grace period and work on another deal.

TikTok is a U.S.-based company, but its primary social media app uses computer source code from ByteDance, including the algorithm that decides which content to promote.

• Stephen Dinan can be reached at sdinan@washingtontimes.com.

• Alex Swoyer can be reached at aswoyer@washingtontimes.com.