The US Senate voted late on Tuesday by a wide margin to send legislation to President Joe Biden that would require Chinese owner ByteDance to divest TikTok's US operations within about nine months or face a ban.

The measure was passed by the US House of Representatives on Saturday and Biden said he would sign it into law on Wednesday.

TikTok, which says it has not shared and would not share US user data with Beijing, has argued the law amounts to a ban that would violate the US free speech rights of its users.

The company did not immediately comment but over the weekend, it told its employees that it would quickly go to court to try to block the legislation.

"We'll continue to fight, as this legislation is a clear violation of the First Amendment rights of the 170 million Americans on TikTok... This is the beginning, not the end of this long process," TikTok told employees on Saturday.

The Senate voted 79 to 18 in favour of the bill.

In 2020, then-President Donald Trump was blocked by the courts in his bid to block TikTok and WeChat in the United States.

The new legislation, however, is likely to give the Biden administration stronger legal footing to ban TikTok if ByteDance fails to divest the app, experts say. It also gives the White House new tools to ban or force the sale of other foreign-owned apps it deems to be security threats.

China has described the proposed US ban on TikTok as unfair.

The Foreign Ministry said last month there is "no fairness to speak of" in citing national security to reduce the competitive advantage of other countries. (Reuters)