NEW YORK (CBSNewYork) — U.S. Customs and Border Protection computers went down at John F. Kennedy International Airport and other airports around the country late Wednesday – leading to major delays.

As CBS2’s Jessica Schneider reported, it turned out the trouble was caused by a problem with the terror watch list.

A federal law enforcement source told CBS News Correspondent Jeff Pegues said the computer system is used to check names of passengers boarding aircraft against the watch list.

A law enforcement source told CBS News a router went offline, and thus, agents had to check names manually.

Many travelers took to Twitter to complain about long lines at check-in points. At the Emirates check-in desks at Terminal 4 at JFK, hundreds of people were stuck on hold.

The scene was the same at airports around the country when the U.S. Customs computers went down around 7 p.m.

“U.S. Customs and Border Protection experienced a temporary outage with its processing systems at air ports of entry in the United States and took immediate action to address the technology disruption. In the meantime, CBP officers processed international travelers using alternative procedures until systems were back on line,” Customs and Border Protection said in a statement. “The outage lasted about 90 minutes. At this time, there is no indication the service disruption was malicious in nature.”

But for travelers, it caused plenty of problems. Harold Schertz was waiting for his mother arriving from Tel Aviv, and said she was stuck in the customs line for 90 minutes.

“She’s waiting to get through Global Entry. She’s standing there waiting. So I have no idea what’s going on,” Schertz said. “She says it’s just bedlam, — the lines are long.”

Joy Rosenstein was flying to Milan, but got backed up in the Emirates line. CBS2 talked to her on the phone.

“The computers are back up. It’s just a large number of people that are traveling long distance and a lot of people have a lot of luggage so I suspect that it will take a little while to catch up,” Rosenstein said.

The outage lasted 90 minutes in all, but was later fixed, and the terror watch list was back up on Customs and Border Patrol online systems.