The National Security Agency collects and analyzes images of people's faces as part of its vast surveillance operation, the agency's director confirmed Tuesday.
But Adm. Mike Rogers insisted that the NSA doesn't intentionally target facial images of Americans.
"We use facial recognition as a tool to help us understand these foreign intelligence targets," Rogers said during an event hosted by Bloomberg.
He said the program does not spy on a "unilateral basis against U.S. citizens." But he acknowledged that some Americans' images are inevitably swept up in the collection.
"Clearly, in the digital age, we will encounter U.S. persons in the wilderness, if you will," he said.
He argued that the program complies with strict legal limitations, including on the collection of data on Americans.
"In broad terms, we have to stop what we're doing if we come to the realization that somebody we're monitoring or tracking has a U.S. connection that we were unaware of," he said.
The New York Times, citing documents provided by Edward Snowden, first reported that the NSA harvests millions of facial images.
According to the documents, NSA leaders believe they must expand their surveillance beyond text and audio.
"It's not just the traditional communications we're after: It's taking a full-arsenal approach that digitally exploits the clues a target leaves behind in their regular activities on the net to compile biographic and biometric information," the agency wrote in one of the documents, The Times reported.
Rogers said the NSA does not have access to any vast databases of Americans' facial images, specifically denying that the agency collects pictures from state DMV offices.
During the event, Rogers called Snowden "arrogant," but said the NSA leaker is "probably" not working on behalf of a foreign nation, such as Russia.