How could a US TikTok ban affect UK users?
TikTok, one of the world's biggest video apps, has gone offline in the US - but could the platform be banned in the UK?
TikTok is restoring its service in the US after briefly going offline on Sunday, after President-elect Donald Trump said he would delay a ban on the social media platform after being sworn in.
The platform, owned by Chinese company ByteDance, stopped working for US users on Saturday before a law put forward by Joe Biden's government over security concerns took effect on Sunday.
But TikTok said it was restoring its service after Trump said he would "extend the period of time before the law's prohibitions take effect, so that we can make a deal to protect our national security".
In a statement, TikTok thanked the President-elect for "providing the necessary clarity and assurance to our service providers that they will face no penalties (for) providing TikTok to over 170 million Americans and allowing over 7 million small businesses to thrive."
In a statement posted on Truth Social, Trump said he would issue an executive order on Monday to extend the period of time before the law’s prohibitions take effect, saying he would like theUS to have a 50% ownership position in a joint venture".
As uncertainty surrounds the long-term future of TikTok in the US, Yahoo News UK breaks down what British app users need to know.
Who owns TikTok?
TikTok was launched to the world by Chinese firm ByteDance in 2017 and quickly racked up hundreds of millions of mobile downloads globally.
Software engineer Zhang Yiming had originally found success creating a property-focused search engine, but in 2012 founded ByteDance. In 2016 it launched video platform Douyin for the Chinese market, with TikTok following a year later for consumers around the rest of the world.
What's happening with TikTok in the US?
TikTok has already seen off one threatened US ban, during Trump's first term in the White House.
As the app's popularity surged in 2020 against the backdrop of the COVID-19 pandemic, the US Commerce Department accused it of being part of "China's civil-military fusion" and said the platform was used to collect "vast swaths of data from users". The Justice Department has argued TikTok represents a "national-security threat of immense depth and scale".
Hostility continued after the election of Joe Biden the same year, culminating in a Senate bill which gave parent company ByteDance a year to either sell up or see TikTok deleted from US app stores, a deadline that passed on Sunday.
People in the US trying to access the app were greeted with the message: "A law banning TikTok has been enacted in the US. Unfortunately that means you can't use TikTok for now."
But the blackout was shortlived, with TikTok issuing a statement saying: "In agreement with our service providers, TikTok is in the process of restoring service," and thanking Trump for "providing the necessary clarity and assurance to our service providers that they will face no penalties (for) providing TikTok to over 170 million Americans and allowing over 7 million small businesses to thrive."
Writing on Truth Social, Trump said: "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.
"The order will also confirm that there will be no liability for any company that helped keep TikTok from going dark before my order.
"Americans deserve to see our exciting Inauguration on Monday, as well as other events and conversations."
He added: "I would like the United States to have a 50% ownership position in a joint venture. By doing this, we save TikTok, keep it in good hands and allow it to say up. Without U.S. approval, there is no Tik Tok. With our approval, it is worth hundreds of billions of dollars - maybe trillions.
"Therefore, my initial thought is a joint venture between the current owners and/or new owners whereby the U.S. gets a 50% ownership in a joint venture set up between the U.S. and whichever purchase we so choose."
What impact could the ban have on UK users?
As the ban would target US app stores, there's no suggestion it would directly affect users in the UK, where technology is regulated by British legislation.
However, the knock-on effects could be huge for the app.
Estimates vary, but the US is the country with the biggest English-language TikTok user base and may be the biggest country for the app overall.
This means that as well as depriving UK users of some of the most popular accounts from across the Atlantic, British content creators also face seeing a huge chunk of their audience disappear overnight.
Some content creators have admitted to "freaking out" over the prospect of the US ban becoming a reality, some of whom have previously left full-time jobs to build careers and incomes around their content and now face an uncertain future.
As a result, many are already attempting to push viewers to alternative apps, such as RedNote.
Could the UK ban TikTok?
If the US ban is upheld by Trump, cybersecurity analysts have suggested it is "just a matter of time" before other countries follow suit.
Pointing to previous cases of Chinese and Russian tech companies being banned on security grounds, Emily Taylor, Editor of the Cyber Policy Journal, told the BBC: "There are big parallels between TikTok and what happened with China's Huawei and Russia's Kaspersky that indicates it's just a matter of time until a creeping ban takes affect."
When Trump's previous administration banned Kaspersky's flagship antivirus software product, and Chinese telecoms firm Huawei, the UK and a number of other allies soon did the same, or at least announced restrictions or warnings.
Insiders and analysts have said that in both cases, there was no evidence that these platforms posed a national security risk, and no evidence has been provided by the US that TikTok has shared user data or edited content in the US for the benefit of the Chinese government.
This time round, however, the UK may go its own way, a Cabinet minister suggested, claiming videos of cats and people dancing do not "seem like a national security threat".
Chief secretary to the Treasury Darren Jones told the BBC's Sunday With Laura Kuenssberg programme: "We have no plans right now to ban TikTok from the UK. So, we won't be following the same path that the Americans have followed unless or until at some point in the future there is a threat that we are concerned about in the British interest."
The UK has already implemented a partial TikTok ban - since 2023 the app has been banned on official devices used by ministers and civil servants. This does not extend to personal devices and exemptions are made for government mobile phones where the app is needed for "work purposes".
What about other countries?
Although owned by a Chinese firm, ByteDance, TikTok does not function in China.
Instead, Chinese users use the company's Douyin counterpart, which follows the censorship rules of the Chinese Communist Party.
Despite at one point being one of the country's most popular apps, in 2020 India banned TikTok following violent clashes between Indian and Chinese troops in a disputed Himalayan border region.
Late last year, Albania became the most recent European country to ban TikTok following the fatal stabbing of a teenager following a row allegedly stoked by the app.
Dozens of other countries have also implemented full bans or, like the UK, barred it from official government devices.