TikTok’s Chinese owner, ByteDance, has until Thursday to sell off its U.S. operations under an executive order that Trump signed in August.

Trump in September gave his tentative blessing to a ByteDance proposal meant to resolve U.S. national security concerns by placing TikTok under the oversight of American companies Oracle and Walmart, each of which would also have a financial stake in the company. But TikTok said this week it’s received “no clarity” from the U.S. government about whether its proposals have been accepted.

The deal has been under a national-security review by the interagency Committee on Foreign Investment in the United States, or CFIUS, which is led by the Treasury Department. The department “remains focused” on resolving the alleged national security risks posed by TikTok, a Treasury spokeswoman said in a statement Wednesday evening.

“With the November 12 CFIUS deadline imminent and without an extension in hand, we have no choice but to file a petition in court to defend our rights and those of our more than 1,500 employees in the US,” TikTok said in a written statement Tuesday.

Trump has cited concerns that the Chinese government could spy on TikTok users if the app remains under Chinese ownership. TikTok has denied it’s a security threat but said it’s still trying to work with the administration to resolve its concerns.

The legal challenge is “a protection to ensure these discussions can take place,” the company said.

The Trump administration had earlier sought to ban the app from smartphone app stores and deprive it of vital technical services, but federal judges have so far blocked those actions.

TikTok is now looking to the U.S. Court of Appeals for the District of Columbia Circuit to review Trump’s divestment order and the government’s national-security review.