STORY: TikTok and Chinese parent company ByteDance are suing the U.S. government to block a law that could see the app banned in the country.

The companies filed their lawsuit in a Washington DC federal court on Tuesday, arguing that the legislation violates the U.S. Constitution on free speech protections, among other grounds.

The law, signed by President Joe Biden on April 24, gives ByteDance until January 19 to sell TikTok or see the app banned in the U.S.

In the lawsuit, the companies complained that the government's singling out of the platform is unprecedented.

They say there was "no question" that the move will QUOTE: "force a shutdown of TikTok by January 19, 2025, silencing the 170 million Americans who use the platform to communicate in ways that cannot be replicated elsewhere."

The administration has said its aim is not to ban the app, but to see Chinese-based ownership ended on national security grounds.

The White House and Justice Department declined to comment on the lawsuit.

In the court filing, the companies said the sale "is simply not possible: not commercially, not technologically, not legally."

They said moving the TikTok source code to the U.S. "would take years for an entirely new set of engineers to gain sufficient familiarity."

Adding that the Chinese government "has made clear that it would not permit a divestment of the recommendation engine that is a key to the success of TikTok in the United States."

The companies are asking the court to block U.S. Attorney General Merrick Garland from enforcing the law.

According to the document, only 21% of Bytedance is owned by the company's Chinese founder.

58% is owned by global institutional investors such as BlackRock, and 21% is owned by employees, including about 7,000 Americans.