Joe Biden has signed legislation banning TikTok, so what happens ...

A ban on TikTok is now almost inevitable in the US as President Joe Biden signs legislation banning the app unless the Chinese-based parent company ByteDance sells the app to an approved buyer. 

Mr Biden's signing sets a January 19 deadline for a sale  — one day before his term is set to expire — but he could extend the deadline by three months if he determines ByteDance is making progress.

Here's the latest: 

Largely, it's a security concern. 

US politicians, law enforcement and intelligence officials have all expressed concerns Chinese authorities could force ByteDance to hand over data from the 170 million Americans who use TikTok.

The worry stems from a set of Chinese national security laws that compel organisations to assist with intelligence gathering.

TikTok has denied sharing US user data.

CEO Shou Zi Chew said the US constitution was on TikTok's side, in a video posted moments after Mr Biden signed the bill. 

"Rest assured — we aren't going anywhere," Mr Chew said.

"The facts and the constitution are on our side and we expect to prevail again.

"Make no mistake — this is a ban on TikTok," he said, emphasising that TikTok would continue to operate as the company challenges the restrictions.

TikTok has already beaten a similar attempt to ban its use in Montana, although the US state is appealing that ruling.

The company plans to challenge this bill as well. 

Mr Biden's re-election campaign plans to continue using TikTok, a campaign official said on Wednesday. Donald Trump's campaign has not joined TikTok.

"A fragmented media environment requires us to show up and meet voters where they are — and that includes online. TikTok is one of many places we're making sure our content is being seen by voters," said a Biden campaign official, who declined to be named.

The campaign will use "enhanced security measures" while using the app, the official said.

Mr Biden's campaign staff are not employed by the government and do not deal with national security issues, so they are allowed to have the app on their phones, campaign officials had previously said.

President Joe Biden plans to continue using TikTok for his re-election campaign. (AP: Evan Vucci)

The Biden campaign account on TikTok, @bidenhq, has posted close to 120 videos and has more than 306,000 followers, and routinely posts videos of Mr Biden there, even as the White House says TikTok causes "legitimate national security concerns."

Since the bill was signed, several users have commented on videos on the account asking "what about TikTok" and pointing out the irony in him posting on the app he just banned. 

Mr Biden signed legislation in late 2022 that barred US government employees from using TikTok on government phones.

A number of US content creators on the app have been protesting the bill at Capitol Hill — others have taken to the app to express their thoughts. 

"There's a core hypocrisy to the Biden administration supporting the TikTok ban while at the same time using TikTok for his campaign purposes,” said Kahlil Greene, who has more than 650,000 followers and is known on TikTok as the "Gen Z Historian".

"I think it illustrates that he and his people know the power and necessity of TikTok," she said. 

TikTok creators like Caleb Simpson are planning for what's next.

Mr Simpson told The Associated Press on Wednesday that a third of his income comes from the app, where he has more than 8 million followers.

For creators like him, the ban would more than impact their livelihood, the app is also where many creators have built relationships and created memories.

About two in 10 US adults said they use TikTok at least once a day, including 44 per cent of 18-29-year-olds. Among 18- 29-year-olds, 7 per cent say they use TikTok "almost constantly" and an additional 28 per cent are using it "several times a day."

Protests have been ongoing at the US Capitol for months. (REUTERS/Craig Hudson)

The measure gives Beijing-based parent company ByteDance nine months to sell the company, with a possible additional three months if a sale is in progress. If it doesn't, TikTok will be banned.

However, if TikTok takes legal action, as it plans to, they will likely ask for an injunction which will push back the deadline of the ban. 

It is unlikely legal proceedings will be complete by the January 19 deadline, so it could take a number of years before the app is completely banned. 

ABC/Wires