The hugely popular video app was taken offline on Saturday night, in compliance with a law that effectively banned the service nationwide unless it splits off from ByteDance, its China-based owner.

Biden officials said that they would leave enforcement of the law up to the Trump administration, and on Sunday morning the app was reinstated, after Donald Trump promised to delay the implementation of a law banning it on national security grounds.

Users were greeted by a message thanking him when they returned to the platform.

"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," TikTok 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."

President-elect Donald Trump wrote on Truth Social that “Americans deserve to see our exciting Inauguration on Monday, as well as other events and conversations."