A U.S. Customs and Border Protection system outage Monday evening caused delays for international travelers at Hartsfield-Jackson International and other airports.

The agency said the outage started at 7:30 p.m. on New Year's Day and ended at around 9:30 p.m. It said officers continued to process international travelers using 'alternative procedures."

Some travelers complained on Twitter about long waits.

Customs and Border Protection said it had access to national security-related databases, but acknowledged that travelers "experienced longer than usual wait times." The agency said there is "no indication the service disruption was malicious in nature."

— Stay up to date on the latest news on Atlanta airline travel by following  Atlanta Airport News Now  on Facebook. U.S. Customs and Border Protection had a temporary outage on the evening of Monday Jan. 1, affecting Hartsfield-Jackson and other airports.