TikTok must now move quickly with a request to the US Supreme Court to block or overturn a law that would require its Chinese parent ByteDance to divest of the short-video app by Jan 19 after an appeals court on Friday rejected a bid for more time.

TikTok and ByteDance on Monday had filed the emergency motion with the US Court of Appeals for the District of Columbia, asking for more time to make their case to the US Supreme Court.

The companies had warned that without court action, the law would “shut down TikTok one of the nation’s most popular speech platforms for its more than 170 million domestic monthly users”.

But the court rejected the bid, saying TikTok and ByteDance had not identified a previous case “in which a court, after rejecting a constitutional challenge to an Act of Congress, has enjoined the Act from going into effect while review is sought in the Supreme Court”, Friday’s unanimous court order said.

A TikTok spokesperson said after the ruling that the company plans to take its case to the Supreme Court, “which has an established historical record of protecting Americans’ right to free speech”.

Under the law, TikTok will be banned unless ByteDance divests it by Jan 19.

The law also gives the US government sweeping powers to ban other foreign-owned apps that could raise concerns about collection of Americans’ data.

The US Justice Department argues “continued Chinese control of the TikTok application poses a continuing threat to national security”.

TikTok says the Justice Department has misstated the social media app’s ties to China, arguing its content recommendation engine and user data are stored in the US on cloud servers operated by Oracle while content moderation decisions that affect US users are made in the United States.

The decision — unless the Supreme Court reverses it — puts TikTok’s fate first in the hands of Democratic President Joe Biden on whether to grant a 90-day extension of the Jan 19 deadline to force a sale, and then of Republican President-elect Donald Trump, who takes office on Jan 20.

Trump, who unsuccessfully tried to ban TikTok during his first term in 2020, said before the November presidential election he would not allow the ban on TikTok.

Also on Friday, the chair and top Democrat on a US House of Representatives committee on China told the CEOs of Google-parent Alphabet and Apple they must be ready to remove TikTok from their US app stores on Jan 19.