An outage hit the Customs and Border Protection's (CBP) computer systems and left international travellers waiting in long lines at airports throughout the US last night.
The outage hit airports including JFK, San Francisco and Denver, even as international travellers arrived from holiday travels on New Year's Day.
CBP said, "there is no indication the service disruption was malicious in nature." It added that all airports came back online after the outage lasted from 7:30 pm to about 9:30 pm ET.
Passengers who landed at the time had to stand in long at the international arrivals area, trying to get through passport control.
"CBP officers continued to process international travelers using alternative procedures at affected airports. Travelers at some ports of entry experienced longer than usual wait times as CBP officers processed travelers as quickly as possible while maintaining the highest levels of security," it said in a statement.
According to the agency it had access to the national security-related databases during the outage.
JFK International, Dallas Fort Worth International as also some others acknowledged the delays on Twitter.
Stranded travellers posted photos on social media of long lines at John F Kennedy International Airport in New York and at Hartsfield-Jackson Atlanta International Airport.
"No one has been getting past JFK Airport immigration for the last hour. Line is a few 100 deep. Seems like their system did completely go down. Happy New Year!" said Jessica Yang, a programme manager at Microsoft, in a Twitter post.
Denver International Airport, also said services had been affected. A similar outage had hit computer systems a year ago.
"Operations returning to normal as @CustomsBorder computer issue resolved. Issue affected other US airports. Thanks for your patience," Miami International Airport said in a Twitter post.