US President Donald Trump on Friday extended the deadline for TikTok to find a non-Chinese buyer or face a ban in the United States, allowing 75 more days to find a solution.

"My administration has been working very hard on a deal to save TikTok, and we have made tremendous progress," Trump said on Truth Social, just hours before the deadline was to expire.

"A transaction requires more work to ensure all necessary approvals are signed, which is why I am signing an Executive Order to keep TikTok up and running for an additional 75 days."

The hugely popular video-sharing app, which has well over 170 million American users, is under threat from a US law that passed overwhelmingly last year and orders TikTok to split from its Chinese owner, ByteDance, or get shut down in the United States.

Trump has insisted his administration is near a deal to find a buyer for TikTok and keep it from shutting down that would involve multiple investors but has given few details.

Motivated by national security fears and belief in Washington that TikTok is controlled by the Chinese government, the ban took effect on January 19, one day before Trump's inauguration.

In the hours before that deadline, TikTok was temporarily shut down in the United States and disappeared from app stores, to the dismay of millions of users.

But the Republican president quickly announced an initial 75-day delay, and TikTok subsequently restored service to users, returning to the Apple and Google app stores in February.

The new 75-day delay pushes the deadline to June 19.

The president added on Friday that he would "continue working in good faith with China."

The president suggested TikTok could even be part of a broader deal with China to ease the stinging tariffs he imposed on Beijing as part of a worldwide blitz of levies.

According to reports, the solution in the works would see existing US investors in ByteDance roll over their stakes into a new independent global TikTok company.

Additional US investors, including Oracle and Blackstone, the private equity firm, would be brought on to reduce ByteDance's share. ABC News reported on Friday that Walmart was also in the mix.

Uncertainty remains, particularly over what would happen to TikTok's valuable algorithm. "TikTok without its algorithm is like Harry Potter without his wand – it's simply not as powerful," said Forrester Principal Analyst Kelsey Chickering.

Amazon has also reportedly made a last-minute bid to buy TikTok. Other proposals include an initiative called "The People's Bid for TikTok", launched by real estate and sports tycoon Frank McCourt's Project Liberty initiative.

Artificial intelligence startup Perplexity recently expressed interest in buying TikTok, as did a joint venture involving YouTube mega-celebrity MrBeast and another bid from adult content platform OnlyFans. (AFP)