Former US President Donald Trump tried to ban the app in 2020, but now opposes plans to restrict it
The TikTok video app is hugely popular with young people around the world.
US politicians are debating legislation that would force TikTok's parent company to sell the app, but former US president Donald Trump has criticised the bill, despite previously supporting a ban.
TikTok is a short form video app that, like YouTube, allows people to post, share and comment on videos.
Since early 2019, TikTok has frequently topped app download charts.
TikTok reached 150 million US monthly active users in March 2023.
The Beijing-based firm is registered in the Cayman Islands, and has offices across Europe and the US. It also owns video editing software CapCut, as well as various other apps that are only available in mainland China - including Douyin, a Chinese version of TikTok.
Like many other social media apps, TikTok collects data from users, but it has faced additional scrutiny over how much it gathers and who can access it.
In 2023 a number of institutions - including the UK government and Parliament, the EU and the US White House - banned staff from using the app on work phones.
If successful, it would require ByteDance to sell TikTok within six months, or face a ban from US app stores and web hosting platforms.
Former US President Donald Trump unsuccessfully tried to ban the app when he was in the White House in 2020.