LONDON (AP) — TikTok is in the crosshairs of authorities in the U.S., where new legislation threatens a nationwide ban unless its China-based parent ByteDance divests. It would be the biggest blow yet to the popular video-sharing app, which has faced various restrictions around the world.

TikTok is already banned in a handful of countries and from government-issued devices in a number of others, due to official worries that the app poses privacy and cybersecurity concerns.

Those fears are reflected in the U.S. bill, which is the culmination of long-held bipartisan fears in Washington that China’s communist leaders could force ByteDance to hand over U.S. user data, or influence Americans by suppressing or promoting certain content. TikTok has long maintained that it doesn’t share data with the Chinese government and its CEO has taken a defiant stance, vowing to fight back.