By Andrew Chung, John Kruzel and David Shepardson WASHINGTON (Reuters) -The Supreme Court upheld on Friday a law banning TikTok in the United States on national security grounds if its Chinese parent company ByteDance does not sell it,

TikTok’s app and website effectively shut down in the United States late Saturday just before a nationwide ban against the video-sharing platform came into force. The company showed its millions of American users a pop-up message that thanked President-elect Donald Trump for indicating he will work with the company on a solution when he takes office on Monday.

President-elect Donald Trump says he “most likely” will give TikTok 90 more days to work out a deal that would allow the popular video-sharing platform to avoid a U.S. ban

Trump announced the decision in a post on his Truth Social account as millions of TikTok users in the U.S. awoke to discover they could no longer access the TikTok app or platform. Google and Apple removed the app from their digital stores to comply with a federal law that required them to do so if TikTok parent company ByteDance didn't sell its U.