TikTok and its Chinese parent company ByteDance filed a suit in US federal court on Tuesday (May 7) seeking to block a law signed by President Joe Biden that would force the divestiture of the short video app used by 170 million Americans or ban its use.

The companies filed their lawsuit in the US Court of Appeals for the District of Columbia Circuit, arguing that the law violates the US Constitution on a number of grounds including running afoul of First Amendment free speech protections.

The law, signed by Biden last month, gives ByteDance until Jan 19, 2025 to sell TikTok or face a ban.

"For the first time in history, Congress has enacted a law that subjects a single, named speech platform to a permanent, nationwide ban," the companies said in the lawsuit.

The lawsuit said the divestiture "is simply not possible: Not commercially, not technologically, not legally ... There is no question: the Act (law) will force a shutdown of TikTok by Jan 19, 2025, silencing the 170 million Americans who use the platform to communicate in ways that cannot be replicated elsewhere".

The White House has said it wants to see Chinese-based ownership ended on national security grounds but not a ban on TikTok. The White House and Justice Department declined to comment on the lawsuit.

The lawsuit is the latest move by TikTok to keep ahead of efforts to shut it down in the United States as companies such as Snap and Meta look to capitalise on TikTok's political uncertainty to take away advertising dollars from their rival.