TikTok went dark for American users in an unprecedented display of the U.S.-China divide over technology and national security.The app started halting service Saturday night for 170 million users in its most important market shortly before a law took effect requiring it to shed its Chinese ownership or close in the U.

TikTok went dark for users across the U.S. late Saturday as the app notified users of a ban that went into effect just days before President-elect Trump's inauguration.