TikTok is resuming services to its 170 million users in US after President-elect Donald Trump said he would issue an executive order to give the app a reprieve when he takes office on Monday.
On Saturday evening, the Chinese-owned app stopped working for American users, after a law banning it on national security grounds came into effect.
But after Trump promised on Sunday to delay the implementation of the law and allow more time for a deal to be made, TikTok said that it was in the process of "restoring service".
It thanked the incoming president for "providing the necessary clarity and assurance" and said the company would work with Trump "on a long-term solution that keeps TikTok in the United States".
Posting on Truth Social, a social media platform he owns, Trump said on Sunday: "I'm asking companies not to let TikTok stay dark! 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."
TikTok's parent company, Bytedance, previously ignored a law requiring it to sell its US operations to avoid a ban. The law was upheld by Supreme Court on Friday and went into effect on Sunday.
It is unclear what legal authority Trump will have to delay the implementation of a law that is already in effect. But it expected that his government will not enforce the ban if he issues an executive order.
For its part, President Joe Biden's administration had already said that it would not enforce the law in its last hours in office and instead allow the process to play out under the incoming Trump administration.
But TikTok had pulled its services anyway on Saturday evening, before the swift restoration of access on Sunday.
The short-form video platform is wildly popular among its many millions of US users. It has also proved a valuable tool for American political campaigns to reach younger voters.
Trump previously backed a TikTok ban, but has more recently professed a "warm spot" for the app, touting the billions of views he says his videos attracted on the platform during last year's presidential campaign.
Under the law passed last April, the US version of the app had to be removed from app stores and web-hosting services if its Chinese owner ByteDance did not sell its US operations.
TikTok had argued before the Supreme Court that the law violated free speech protections for its users in the country.
The law was passed with support from both Republicans and Democrats in Congress and was upheld unanimously by Supreme Court justices earlier this week.
The issue exposes a rift on a key national security issues between the president-elect and members of his own party. His pick for Secretary of State, Marco Rubio, had vocally supported the ban.
"TikTok extended the Chinese Communist Party's power and influence into our own nation, right under our noses," he said last April.
After Trump intervened on Sunday morning, Senate Intelligence Committee Chair Tom Cotton, a Republican senator from Arkansas, broke with Trump by saying that any company that helps TikTok stay online would be breaking the law.
"Any company that hosts, distributes, services, or otherwise facilitates communist-controlled TikTok could face hundreds of billions of dollars of ruinous liability under the law, not just from DOJ, but also under securities law, shareholder lawsuits, and state AGs," he wrote on social media.
BBC