McCarran International Airport in the US has installed facial-feature and fingerprint scanning devices at its terminal 2.
The systems have been installed by US Customs and Border Protection as part of a pilot programme to expedite legal permanent residents of the US.
In order to use the systems, passengers must register, be photographed and have their fingerprints scanned and put in the customs database.
Passengers must pay $100 for five-year registation for the new service, which is called Global Entry.
The same system has been already installed at Atlanta, Chicago's O'Hare, Houston Intercontinental, Los Angeles, New York's John F Kennedy, Miami and Washington-Dulles International Airports.