Senate Minority Leader Charles Schumer (D-NY) speaks after the weekly Democratic policy luncheon at the U.S. Capitol March 26, 2019 in Washington, DC.

Users' photos can be edited to make a user look older or younger or to change their gender, he said.

FaceApp's artificial intelligence application for editing photos requires users to provide it with "full and irrevocable access to their personal photos and data," which could pose "national security and privacy risks for millions of U.S. citizens," Schumer said in his letter to FBI Director Christopher Wray and FTC Chairman Joe Simons.

U.S. Senate minority leader Chuck Schumer called on the FBI and the Federal Trade Commission to conduct a national security and privacy investigation into Russia -based FaceApp, whose mobile software application alters users' photos, in a letter sent on Wednesday.

"FaceApp's location in Russia raises questions regarding how and when the company provides access to the data of U.S. citizens to third parties, including potentially foreign governments, " Schumer said in the letter.

It is not clear how the artificial intelligence application retains the data of users or how users may ensure the deletion of their data after usage, Schumer said.

Schumer said the photo editing app's location in Russia raises questions about how FaceApp lets third parties, including foreign governments, have access to the data of American citizens.

In a statement cited by media outlets, FaceApp has denied selling or sharing user data with third parties.

"99% of users don't log in; therefore, we don't have access to any data that could identify a person", the company said in a statement cited by TechCrunch, adding that most images are deleted from its servers within 48 hours of the upload date.

While the company's research and development team is located in Russia, the user data is not transferred to Russia, according to the statement.

FaceApp's website says it has over 80 million active users. FaceApp's website promotes the app by saying: "Transform your face using Artificial Intelligence with just one tap," showing photos with changes in users' appearances.