When the computers went down at 1:30 p.m., security personnel had no way of finding passengers who were supposed to get extra attention, The Los Angeles Times reported.

Mike Fleming, a spokesman for Immigration and Customs Enforcement, said most incoming passengers are no security risk.

"But it only takes one," he added.

Passengers were forced to remain on airplanes for several hours or to crowd into packed customs areas.

The computer problems affected all terminals with incoming traffic at LAX but no other airports. Fleming said airlines were allowed to supply planes with food and beverages for stranded passengers.