The United Arab Emirates is using one of the most popular messaging apps in the United States to track the conversations, locations, and interactions of all of the app’s users.

The app ToTok became one of the most downloaded messaging apps in the U.S. last week on both Apple and Google’s app store. The app, sold as a safe and secure way to communicate, is being used by the U.A.E. to spy on its own people and others around the world, according to the New York Times.

ToTok is most popular in the U.A.E., but also serves millions of users in Africa, Asia, Europe, the Middle East, and North America. The company that created ToTok, Breej Holding, is believed to be a front group for an Abu Dhabi-based hacking firm called DarkMatter. The firm employees ex-cyberintelligence employees from the Emirates, Israel, and the U.S. National Security Agency.

Google and Apple have pledged to look into the popular app. Google removed it from its store on Thursday, and Apple followed suit on Friday.

ToTok is a close copy of a Chinese app called YeeCall but adapted for a different audience, according to an analysis by a former NSA hacker.