International passengers arriving at DFW International airport and other U.S. airports experienced long lines Monday evening due to an apparent outage impacting U.S. Customs and Border Protection computer systems.

In a tweet from DFW Airport: 'there is a system issue affecting processing times for customs. The customs agents are working to get everyone screened and through customs as quickly as possible. Your patience is appreciated.'

The disruption happened at several airports beginning at 6:30 p.m. and was resolved at around 8:30 p.m., according to a release from Customs.

During the outage, 'alternative procedures' were used to process international passengers, according to the agency. 'At this time, there is no indication the service was malicious in nature.'

American Airlines said it is aware of the issues which did not result in flight delays or cancelations.

Denver International Airport reported the “brief customs processing issue has been resolved.”

This is a developing story — refresh for updates as they come available