Who owns Tiktok and what must they do to avoid US ban?
In one of the first acts of his second term, Donald Trump gave the social media app - which is owned by the Chinese company ByteDance - a reprieve.
The disappearance of popular video app TikTok in the US this week was brief taster of the looming ban that still awaits it - despite President Donald Trump giving it a reprieve.
Trump signed an executive order on Monday that seeks to delay the ban by 75 days after TikTok briefly went offline on Sunday.
The app is used by 170 million people in the US and an estimated two billion worldwide, and the potential US ban has led some experts to suggest that other territories might ban the Chinese-owned app.
TikTok chief executive Shou Zi Chew attended Trump's inauguration this week, along with other big tech' leaders such as Elon Musk and Mark Zuckerberg.
Authorities in the US have long feared China could be using the app to collect vast amounts of data on American citizens and banning it had wide support from both parties in Congress.
When pressed on what he would say to people who believe the app is used to spy on Americans by Fox News Trump said: "You could say that about everything made in China, we have our telephones made in China.
"We have so many things made in China, why don't they mention that?"
He went on to say: "Is it that important for China to be spying on young people on young kids watching crazy videos?"
What's the latest?
While the app is back online in the wake of the weekend's blackout, it remains unavailable on both the Apple App Store and Google's Play Store.
A notice on Apple's App Store said: "TikTok and other ByteDance apps are not available in the country or region you're in".
Google Play showed a message saying: "Downloads for this app are paused due to current US legal requirements."
Users of eBay have listed devices with the app pre-installed for sale at up to $50,000 (£40,000).
Other apps from ByteDance, the company which owns TikTok, remain unavailable, including the popular video-editing app CapCut and social media app Lemon8.
Who are TikTok owners ByteDance?
ByteDance is a Chinese social media company founded in 2012 and based in Beijing.
As well as TikTok and its Chinese equivalent Douyin, it also produced apps such as the video-editing app CapCut.
The company is estimated to be valued at $300 billion (£243bn) and has come under US government scrutiny over fears of surveillance by the Chinese government.
US legislators last year passed a law upheld by the US Supreme Court requiring ByteDance to either sell TikTok or face a ban. Many Democratic and Republican politicians still want to see ByteDance sell the app.
ByteDance's global revenue grew to $110 billion (£89 billion) last year, a rise of 30%.
ByteDance founder Zhang Yiming, who stepped aside as chief executive in 2021, is China's richest person.
Trump previously met with current TikTok CEO Shou Zi Chew in December, hours after the president-elect said he had a "warm spot" for the app and that he favoured allowing TikTok to keep operating in the United States for at least a little while.
The then-president-elect also said he had received billions of views on the social media platform during his presidential campaign.
Who could buy TikTok's US operation?
Trump has said he is open to the idea of billionaire Elon Musk buying TikTok if the company’s CEO is open to it. Bloomberg News previously reported that Chinese officials were in talks about a potential option to sell TikTok's operations in the United States to Musk.
The company has denied this.
While signing the order, Trump even suggested the United States government should have a 50% stake in TikTok's US business.
The deal would be in exchange for keeping the app operational in the US, while Trump has warned that he could impose tariffs on China if Beijing failed to approve a US deal with TikTok.
One deal on the table is from billionaire businessman Frank McCourt's Project Liberty consortium, which has valued the app without its algorithm at around $20 billion (£16bn). In an interview with CNBC on Tuesday, one senior consortium figure, Kevin O'Leary, said he would be interested in a TikTok deal, but it's not possible under current law.
"That 50/50 deal, I would love to work with Trump on, so would every other potential buyer ... But the problem with some of these ideas is they are inconsistent with the ruling of the Supreme Court," he said.
Another buyer to emerge is YouTube star MrBeast, who has joined tech entrepreneur Jesse Tinsley - founder of the online HR company employer.com - to make an all-cash offer.
What happens next?
Following Trump's remarks the Chinese Foreign Ministry, which previously stated it would block a forced sale, responded by saying companies can make their own decisions.
This marks the first indication that Beijing would be open to a US deal.
However, it's not clear whether Trump's executive order is legal.
For one thing, it would be unprecedented for the US government to demand an equity stake in a major company in exchange for approving its continued use.
The law requiring the sale of ByteDance US was passed by big majorities in Congress, signed by President Joe Biden, and upheld by a unanimous vote in the Supreme Court.