A new U.S. law banning TikTok has come into effect, hours after the popular app stopped working across the country.

Late on Saturday, a message appeared on TikTok for U.S. users saying a law banning TikTok had been enacted, meaning “you can’t use TikTok for now.”

The video-sharing app was banned over concerns about its links to the Chinese government.

It was given until January 19 to be sold to an approved U.S. buyer to avert the ban.

President Joe Biden had said he would leave the issue to his successor, Donald Trump.

The president-elect has said he will “most likely” give TikTok a 90-day reprieve from a ban once he takes office on Monday.

Users reported the app had also been removed from both Apple and Google’s U.S. app stores, and TikTok.com was not showing videos, in line with the terms of the ban.

It is the first time the U.S. has banned a major social media platform.