TikTok and its Chinese parent ByteDance said on Tuesday that they had filed a lawsuit against the US government challenging a law that would force a sale or ban of the app.

Last month, Washington passed legislation requiring TikTok to divest from its parent by January 19 2025 or face a countrywide ban, citing concerns that the Chinese Communist party could wield data on the app’s 170mn US users for espionage purposes, or proliferate propaganda via the platform.

In a petition, filed with the US Court of Appeals for the District of Columbia Circuit and posted on its website, TikTok claimed that the law was unconstitutional, breaching First Amendment free speech rights. It also argued that Congress had “enacted these extreme measures without a single legislative finding”, and that the act would constitute “unlawful taking of private property”.