Using a new facial recognition system implemented just days earlier, US Customs and Border Protection (CBP) officers on Wednesday stopped an imposter who attempted to enter the US with someone else's passport.

The 26-year-old man, who was traveling from Sao Paulo, Brazil, presented a French passport to the CBP officer conducting primary inspections, but the new "cutting-edge facial comparison biometric system" confirmed he wasn't a match to the document, the agency said in a Thursday news release.

"The CBP officer referred the traveler to secondary for a comprehensive examination," the agency wrote. "In secondary, CBP officers noted the traveler's behavior changed and he became visibly nervous. A search revealed the man's authentic Republic of Congo identification card concealed in his shoe."

On Monday, CBP started using the new facial recognition technology at 14 early adopter airports. The system is designed to "provide additional security and to improve efficiency for international travelers."

In the future, the technology may be used throughout the airport security and boarding processes, so travelers are identified via biometrics instead of their boarding pass and ID, CBP said. The agency is deploying the new technology to verify travelers' identities "both upon arrival in, and departure from" the US.

Before departing, you stand in front of a camera and have your photo taken. The image is then matched against the photo on your passport. CBP said the "biometric matching service is hosted in a secure cloud-based environment." The agency discards photos of US citizens within 12 hours after their identities have been verified and deletes photos of non-US citizens within 14 days.

At this time, US citizens are not required to have their photos captured when entering or exiting the country. If you do not want to participate in the biometric entry or exit process, notify a CBP officer or an airline or airport representative and ask to be processed using alternate procedures.

"Facial recognition technology is an important step forward for CBP in protecting the United States from all types of threats," CBP Director of the Baltimore Field Office Casey Durst said in a statement. "Terrorists and criminals continually look for creative methods to enter the U.S. including using stolen genuine documents. The new facial recognition technology virtually eliminates the ability for someone to use a genuine document that was issued to someone else."