WASHINGTON, United States (AFP) —TikTok says it will “go dark” in the US on Sunday, threatening access to the app for 170 million users, unless the government provides assurances that a law mandating its sale or ban won’t be used to punish service providers.

After months of legal tussles, the US Supreme Court on Friday upheld a law that would ban the popular video-sharing platform in the name of national security, unless its Chinese owners reach an 11th-hour deal to sell it to non-Chinese buyers by Sunday.

Only months after overwhelmingly backing the law, lawmakers and officials were now fretting about the ban, with all eyes on whether US President-elect Donald Trump can swoop in and find a way to save the app.

From teenage dancers to grandmothers sharing cooking tips, TikTok has been embraced for its ability to transform ordinary users into global celebrities when a video goes viral.

It is also appreciated by Trump, who has credited the app with connecting him to younger voters, contributing to his election victory in November.

Trump discussed TikTok with Chinese President Xi Jinping on Friday and said he would need more time to find a solution.

“My decision on TikTok will be made in the not too distant future, but I must have time to review the situation. Stay tuned!” Trump said in a social media post.

Late on Friday, however, TikTok said its US services would “go dark” unless the Biden administration “immediately provides a definitive statement to satisfy the most critical service providers assuring non-enforcement” of the law calling for the platform’s ban.

The administration of outgoing President Joe Biden, who leaves office on Monday, has said it will leave the matter to Trump’s incoming government.

After the court defeat, TikTok CEO Shou Chew appealed to Trump, thanking him for his “commitment to work with us to find a solution.”