WASHINGTON (Reuters) -A U.S. appeals court on Friday rejected an emergency bid by TikTok to temporarily block a law that would require its Chinese parent company ByteDance to divest the short-video app by Jan. 19 or face a ban on the app.

TikTok and ByteDance on Monday filed the emergency motion with the U.S. Court of Appeals for the District of Columbia, asking for more time to make its case to the U.S. Supreme Court. Friday's ruling means that Tiktok now must quickly move to the Supreme Court in an attempt to halt the pending ban.

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

"The petitioners have not identified any 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," the D.C. Circuit said.

TikTok did not immediately respond to a request for comment.

Under the law, TikTok will be banned unless ByteDance divests it by Jan. 19. The law also gives the U.S. government sweeping powers to ban other foreign-owned apps that could raise concerns about collection of Americans' data.

The U.S. 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 U.S. on cloud servers operated by Oracle while content moderation decisions that affect U.S. users are made in the U.S.