Apple Inc. and Google removed TikTok from their mobile app stores in the US as required by a law that took effect Sunday, after the social media company’s legal challenges failed to head off the measure passed last year to address national security concerns.

With TikTok, CapCut, and Marvel Snap shut down in the US, Apple has taken the unusual step of articulating why it’s following the law banning ByteDance apps and removing them from the App Stores for the Mac, iPhone, and other devices.