Travelers to the U.S. from overseas were experiencing delays in passing through customs at major airports on Friday, thanks to a technology outage affecting U.S. Customs and Border Protection (CBP) stations.
"CBP is experiencing a temporary outage with its processing systems at various air ports of entry & is taking immediate action to address the technology disruption," the agency said on Twitter shortly after 5 p.m. ET. "CBP officers continue to process international travelers using alternative procedures until systems are back online."
"CBP officers are working to process travelers as quickly as possible while maintaining the highest levels of security."
Travelers at airports around the country -- including at Kennedy International Airport in New York, Dulles International Airport in Virginia, Charlotte Douglas and Raleigh-Durham International Airports in North Carolina and Hartsfield-Jackson Atlanta International Airport in Georgia -- expressed frustration about significant delays and long lines at international arrivals halls even as CBP warned that "arriving travelers at some ports of entry are experiencing longer-than-usual wait times."
CBP said it was processing passengers manually.
One passenger at Dulles posted a video of masses of travelers waiting in snaking lines to reach immigration processing counters.
"Easily 5,000+ passengers in line at Dulles," she estimated.
A spokesman for the Metropolitan Washington Airports Authority told Fox News that "about 3:30 p.m. EDT ... Customs and Border Protection was experiencing a nationwide computer issue affecting their ability to process arriving international passengers, including at Dulles International Airport ... Airport operations remain normal at this time."
Another passenger, one arriving at JFK, said "The system is allegedly down, including global entry. It’s hot. No air. In a narrow hallway. People were backing up on the escalator and falling over each other."
Officials at Los Angeles International Airport tweeted Friday afternoon that 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."
Shortly after 6 p.m. ET, the airport tweeted that systems were slowly getting back to normal, and that officers had processed the majority of waiting passengers with no significant impacts to flights.
"Thank you for your patience."
Fox News' Alexandra Pamias and The Associated Press contributed to this report.