WASHINGTON, United States (AFP)— The US Supreme Court on Friday upheld a law that will ban TikTok in the United States, potentially denying the video-sharing app to 170 million users in two days.

In a major defeat for TikTok, the court ruled that the law does not violate free speech rights and that the US government had demonstrated legitimate national security concerns about a Chinese company owning the app.

The Supreme Court last week heard arguments from the company, ByteDance, that the law should be stopped because it was a violation of free speech.

“There is no doubt that, for more than 170 million Americans, TikTok offers a distinctive and expansive outlet for expression, means of engagement, and source of community,” the justices said.

“But Congress has determined that divestiture is necessary to address its well-supported national security concerns regarding TikTok’s data collection practices and relationship with a foreign adversary,” they concluded.

With that decision, Sunday’s ban effectively stands even if lawmakers and officials across the political spectrum were calling for some sort of delay.

Congress overwhelmingly passed a law last year forcing ByteDance to either sell the platform or close it in the United States by January 19.

The law was an answer to widespread belief in Washington that the highly popular app could be used by China for spying or propaganda.

White House officials on Friday told US media that they would not enforce the ban and leave it up to President-elect Donald Trump, who takes office a day later.

Trump said that he discussed TikTok in a phone conversation with Chinese President Xi Jinping on Friday.

Speaking to Fox News on Thursday, Trump’s incoming national security advisor Mike Waltz said the administration would put in place measures “to keep TikTok from going dark.”

“The legislation allows for an extension as long as a viable deal is on the table,” he said. “Essentially that buys president Trump time to keep TikTok going.”

“It’s been a great platform for him and his campaign to get his America first message out,” he added. “But at the same time, he wants to protect (users’) data.”

Senate Democratic Leader Chuck Schumer on Thursday also called for a looming TikTok ban to be delayed.

“It’s clear that more time is needed to find an American buyer and not disrupt the lives and livelihoods of millions of Americans, of so many influencers who have built up a good network of followers,” Schumer said.

To execute the ban, the US government would direct Apple and Google to remove TikTok from their app stores, preventing new downloads starting the day before Trump takes office.

TikTok lawyer Noel Francisco stated the site would “go dark” on Sunday if the justices fail to block the ban, and a media report said the company was planning a full suspension of service in the United States.

Campaigning ahead of the November election, Trump pledged to save TikTok and his team has been mulling ways to stall the ban or rescue the app.

Once Trump takes office, the law’s implementation will fall to his attorney general, who could choose not to enforce it, or stall, defying Congress’s support for the legislation.

TikTok has been lobbying furiously to thwart the law’s implementation and CEO Shou Chew will attend Trump’s inauguration on Monday.

TikTok did not respond to a request for comment.