The federal government began tracking foreigners leaving the United States through Dallas/Fort Worth Airport on Thursday.
The exit kiosks -- where foreign travelers scan their travel documents and are photographed and fingerprinted -- are in the testing phase, said Danielle Sheahan, a spokeswoman for the Bureau of Customs and Border Protection.
Also being tested are wireless scanning devices operated by private contract workers.
Airports in Baltimore, Chicago and Denver started the pilot program earlier, said Anna Hinken, US-VISIT outreach manager for the Homeland Security Department.
Since January, the government has fingerprinted most foreigners coming into international airports such as D/FW. The new program is the first U.S. attempt to monitor those leaving.
The exit kiosks resemble ATMs, into which international travelers insert their travel documents. When they have been fingerprinted and photographed, they get a receipt.