Updated at 7:25 p.m. ET
The computer systems of Customs and Border Protection are returning at major airports around the country.
"The affected systems are coming back online and travelers are being processed," a CBP statement said. "There is no indication the disruption was malicious in nature at this time."
Earlier the agency said it had a temporary outage at "various air ports of entry. ... CBP officers continue to process international travelers using alternative procedures until systems are back online."
The problem was initially reported at airports in New York, Los Angeles, San Francisco and Washington, D.C.