Immigration desk computers at various airports went down for about two hours on Monday, causing long lines for travellers entering the United States after year-end holidays, according to Customs and Border Protection and posts on social media.

The processing system outage began at about 7:30 p.m. EST and was resolved about 9:30 EST, the customs agency said in a statement. All airports were back online after wait times for travellers that were longer than usual, it said.

“At this time, there is no indication the service disruption was malicious in nature,” the agency said. It gave no explanation for the disruption and said travellers were processed using alternative procedures.

Travelers entering the United States from overseas posted photos on social media of long lines at John F. Kennedy International Airport in New York and at Hartsfield-Jackson Atlanta International Airport.

Other airports, including Denver International Airport, also said they were affected. A similar computer outage occurred a year ago.