The U.S. Senate approved on Tuesday a bill aimed at forcing a change of ownership of the popular video-sharing app TikTok, owned by Chinese internet company ByteDance, by which, if not sold, the platform would face an outright ban in the United States.

The U.S. Senate approved the bill with 79 votes in the 100-seat upper chamber. It will now go to U.S. President Joe Biden, who said he would sign it into law if it reached his desk.

At that point, China's ByteDance group, which owns the app, will have up to one year to divest itself of TikTok. If the service remained in the group's possession, the law would lead to TikTok being banned from U.S. app stores.

The measure was passed as part of a broader bill that also included a Ukraine weapons aid package. The TikTok divestment directive, introduced just weeks ago, won fast-track approval.

Skeptics of the measure point out that the law will likely spend years in the courts, saying it will surely be challenged on the basis of free speech protections enshrined in the U.S. Constitution.

There have been years of fears in Washington about ByteDance's access to user data.

Some cybersecurity experts say Beijing could use the data to spread propaganda in the U.S., spy on users and exercise other forms of influence.

Critics counter that the Chinese founders, with a share of 20%, have control thanks to higher voting rights and that ByteDance has large headquarters in Beijing.

TikTok, which says it has 170 million U.S. users, rejects concerns and emphasizes that it does not see itself as a subsidiary of a Chinese company. ByteDance is 60% owned by Western investors. The company is based in the Cayman Islands in the Caribbean.

The four-year battle over TikTok is just one front in a war over the internet and technology between Washington and Beijing. Last week, Apple said that Beijing ordered Meta Platforms' WhatsApp and Threads to be removed from its App Store in China due to Chinese national security concerns.

TikTok is likely to challenge the bill on First Amendment grounds, and users are also expected to take legal action again. In November, a U.S. judge in Montana blocked a state ban on TikTok, citing free speech grounds.

The American Civil Liberties Union said banning or requiring divestiture of TikTok would "set an alarming global precedent for excessive government control over social media platforms. ...If the U.S. now bans a foreign-owned platform, that will invite copycat measures by other countries."

TikTok, which says it has not shared and would not share U.S. user data with the Chinese government, did not immediately comment but has told employees it would quickly go to court to try to block the legislation.

"This is the beginning, not the end of this long process," TikTok told staff on Saturday in an email seen by Reuters.

In 2020, then-President Donald Trump was blocked by the courts in his bid to block TikTok and Chinese-owned WeChat, a unit of Tencent in the U.S.

However, experts say the new legislation is likely to give the Biden administration a stronger legal basis to ban TikTok if ByteDance fails to divest the app.

If ByteDance failed to divest TikTok, app stores operated by Apple, Alphabet's Google and others could not legally offer TikTok or provide web hosting services to ByteDance-controlled applications or TikTok's website.

The bill would also give the White House new tools to ban or force the sale of other foreign-owned apps it deems security threats.

Democratic Sen. Ron Wyden said he was concerned the bill "provides broad authority that could be abused by a future administration to violate Americans' First Amendment rights."

Once the bill is signed into law, ByteDance will have 270 days to divest TikTok's U.S. operations with a possible three-month extension if there are signs a deal is progressing.

Democratic Sen. Ed Markey said it would be hard, if not impossible, for ByteDance to divest by early 2025, adding that a sale would be one of the most complicated and expensive transactions in history, requiring months, if not years, of due diligence.

"We should be very clear about the likely outcome of this law. It's really just a TikTok ban," he said. "Censorship is not who we are as a people. We should not downplay or deny this trade-off."

The bill could also be an issue in the November presidential campaign, with Republican presidential candidate Trump urging young voters to take notice of a possible TikTok ban.