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

TikTok and ByteDance had filed the emergency motion with the U.S. Court of Appeals for the District of Columbia on Monday, asking for more time to make their case to the U.S. 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 January 19. The law also gives the U.S. government sweeping powers to ban other foreign-owned apps that could raise concerns about the collection of Americans' data.

The U.S. Justice Department argues that "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 U.S. on cloud servers operated by Oracle, while content moderation decisions that affect U.S. 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 January 19 deadline to force a sale, and then of Republican President-elect Donald Trump, who takes office on January 20.

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

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