The Justice Department late on Wednesday asked a US appeals court to reject 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.

TikTok and ByteDance on Monday filed the emergency motion with the US Court of Appeals for the District of Columbia pending a review by the US Supreme Court. They 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 Justice Department said the court should not delay the law's effective date arguing "continued Chinese control of the TikTok application poses a continuing threat to national security."

TikTok did not immediately respond to a request for comment.

DOJ said Wednesday if the ban takes effect on Jan. 19 it would "not directly prohibit the continued use of TikTok" by users who had downloaded TikTok but it conceded that the effect of the prohibitions on providing support "will eventually be to render the application unworkable."

On Friday, a three-judge panel of the appeals court upheld the law requiring ByteDance to soon divest TikTok in the United States face a ban in just six weeks.

The companies noted President-elect Donald Trump has vowed to prevent a ban, arguing the delay "will give the incoming administration time to determine its position."

The decision - unless the Supreme Court reverses it - puts TikTok's fate first in the hands of President Joe Biden on whether to grant a 90-day extension of the Jan. 19 deadline to force a sale and then of 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.

The decision upholds the law that gives the US government sweeping powers to ban other foreign-owned apps that could raise concerns about collection of Americans' data. In 2020, Trump also tried to ban Tencent-owned (0700.HK), opens new tab WeChat, but was blocked by the courts.