The FBI stated that FaceApp and other mobile applications developed in Russia present a “potential counterintelligence threat.”
The observations were made in a letter to US Senator Chuck Schumer after he asked for an investigation into the app.
Previously this year, the face-editing tool went viral but triggered privacy concerns.
The FBI comments turn up amid rising US concerns that products created by foreign tech firms could pose security threats.
In a letter referred to Mr Schumer, the agency said, “it deems any mobile application or similar product made in Russia, such as FaceApp, to be a possible counterintelligence threat.”
The FBI also added it would act if it found any proof of foreign political snooping through the application, which changes users’ photos to make them look younger or older.
FaceApp did not instantly respond to invitations for comment.
The app was made by Wireless Lab, a company established in St Petersburg. The company earlier said it does not permanently store pictures, and does not collect heaps of data – only uploading particular photos chosen by users for editing.
Senate minority chief Mr Schumer called for an inquiry into FaceApp in July over fears it could pose “privacy and national security risks for millions of US citizens”.
It comes during wider inspection of foreign technology products in the US.
Lately, lawmakers have targeted TikTok, a video-sharing platform possessed by China’s ByteDance.
The application, expected to have about half a billion active users globally, has risen in popularity in current years.
That rise in popularity has caused uneasiness in Western markets due to the nature of its Chinese ownership.
US lawmakers, counting Mr. Schumer, in October, demanded that “the intelligence community carry an assessment of the national security risks posed by TikTok and other China-possessed content platforms in the US.”