(Adds details on outage, service restored, no indication the outage was malicious)
Jan 2 (Reuters) - A U.S. Customs and Border Protection (CBP) computer problem lasting about four hours hit several U.S. airports on Monday, causing long lines and delays at immigration checks as travelers returned from New Year's holidays, the agency said.
"At this time, there is no indication the service disruption was malicious in nature," a spokeswoman said in a statement.
The delay hit from about 5 p.m. to 9 p.m. U.S. Eastern Standard Time (2200 GMT to 0200 GMT Tuesday) and all airports are back on line, the statement from spokeswoman Jennifer Evanitsky said.
Airports in places such as New York, Los Angeles, Miami, Boston and Atlanta were affected, local airport officials said.
"During the technology disruption, CBP had access to national security-related databases and all travelers were screened according to security standards," the spokeswoman said.
Social media photos showed long lines at various airports where people were trying to go through immigration and customs. (Reporting by Jon Herskovitz in Austin, Texas; Editing by Nick Macfie and Michael Perry)