U.S. Customs and Border Protection has issued a statement saying a processing system outage caused delays at various airports.

The statement says CBP officers continued processing international travelers using “alternative procedures” until the system came back online Monday but waits were longer than usual at some airports.

In Atlanta, CBP public affairs officer Robert Brisley says the outage at the city’s airport lasted about an hour from late afternoon into early evening. He said that officers were working to recover quickly afterward but even short outages can lead to backups at the airport, one of the world’s busiest.

He said the agency apologizes to travelers who were delayed getting into the country after long flights.

Brisley said the cause of the outage was still being evaluated.

This article was from The Associated Press and was legally licensed through the NewsCred publisher network.

Tags: customs
Photo Credit: U.S. airports experienced delays processing arriving passengers January 2, 2017 because of a system outage. In this Thursday, May 19, 2016, photo, travelers move through a security checkpoint line at Hartsfield-Jackson Atlanta International Airport in Atlanta. David Goldman / Associated Press