He tweeted: "A warning to share with your family & friends: This year when millions were downloading #FaceApp, I asked the FBI if the app was safe. Well, the FBI just responded. And they told me any app or product developed in Russia like FaceApp is a potential counterintelligence threat."
He went on to share a letter from Jill C Tyson, Assistant Director of the Office of Congressional Affairs, outlining the concerns.
The letter added that the FBI "considers any mobile application or similar product developed in Russia, such as FaceApp, to be a potential counterintelligence threat".
The app was developed by Wireless Lab, a company based in St Petersburg, Russia.