TikTok is informing its users that the app will be temporarily inaccessible due to an impending ban in the U.S. that kicks in on Sunday.

When users log in, they encounter a pop-up message stating “Important update from TikTok,” which explains that the new U.S. law will “force us to make our services temporarily unavailable. We’re striving to restore our service in the U.S. as quickly as possible.” On Saturday, users could still proceed through the message and continue using the app.

The time until the app goes offline seems inevitable, after the U.S. Supreme Court unanimously backed Congress’ decision to ban TikTok unless the app’s U.S. assets are sold by January 19. President Joe Biden indicated he would not enforce the ban, leaving the decision to President-elect Donald Trump, who is set to be inaugurated on Monday and mentioned to NBC News that he is likely to impose a 90-day delay.

“We regret that a U.S. law banning TikTok will take effect on January 19 and force us to make our services temporarily unavailable,” reads the pop-up notification. “We are working diligently to restore our service in the U.S. as soon as possible and appreciate your understanding. Please stay tuned.”

As of Saturday at 9 pm ET, the social media platform remains operational in the U.S., although its future is uncertain.

The move to ban TikTok, which has 170 million users in the U.S., arises from national security concerns among U.S. officials regarding the extent of control the Chinese government may have over the firm.

TikTok is a subsidiary of ByteDance, a global private company headquartered in Beijing founded by Chinese entrepreneurs. According to TikTok, approximately 60% of the parent company is owned by international institutional investors, with 20% held by its founders and 20% by employees.

This story has been revised to correct a typo.

Contributing: Jonathan Limehouse, Mike Snider, Greta Cross, Clare Mulroy, Maureen Groppe & Rebecca Morin