U.S. Customs and Border Protection’s computers systems shut down nationwide on Friday, prompting widespread delays at airports across the country.

New York City’s John F. Kennedy Airport confirmed the computers were down and said officials were moving quickly to get its system up and running.

LAX also confirmed its CBP computers were offline, writing on Twitter: “.@CBP systems are experiencing an issue which appears to be impacting multiple airports including LAX. Officers are processing passengers manually so please check with your airline for the latest status of any flight impacts. More details as they become available.”

.@CBP systems are experiencing an issue which appears to be impacting multiple airports including LAX. Officers are processing passengers manually so please check with your airline for the latest status of any flight impacts. More details as they become available. — LAX Airport (@flyLAXairport) August 16, 2019

Bush Intercontinental Airport in Houston, Texas, O’Hare Airports in Chicago, Illinois, and Philadelphia International Airport have all reported computer issues as well.

Travelers took to Twitter to share videos of the long lines caused by the shutdown.

#Breaking: Long lines seen at Philadelphia International Airport as U.S. Customs and Border Patrol confirmed a computer issue was causing delays across the country. https://t.co/ocZvumjn6D pic.twitter.com/ED1I3DAxUn — NBC10 Philadelphia (@NBCPhiladelphia) August 16, 2019

Here’s a better perspective of the customs line at JFK. People are growing frustrated. Nothing like landing after a 10 hour flight to this. pic.twitter.com/WrEUsoJhbH — Sarah Baird 🙌 (@Baird_S) August 16, 2019

Nationwide outage of US CBP computer systems. Easily 5,000+ passengers in line at Dulles. pic.twitter.com/JGJD95sfFx — Rebekah Tromble (@RebekahKTromble) August 16, 2019

The cause of the computer outage is presently unclear.