Weary international passengers were stuck at Los Angeles International Airport for several hours, unable to set foot in the United States after a computer failure prevented customs officials from screening arrivals.

About 11,500 international passengers, both Americans and foreigners, sat in four airport terminals and in 60 planes starting about 2 p.m. on Saturday, when the computer system broke down, said Los Angeles World Airports spokesman Paul Haney.

The system contains names of arriving passengers and law enforcement data about them, including arrest warrants, said Mike Fleming, a U.S. Customs and Border Protection spokesman.

"That system allows our officers to make decisions on who we can allow to enter the United States," Fleming said. "You just don't know by looking at them."

The computers were fully restored at 11:45 p.m., and the last of backlogged passengers were expected to be cleared by early Sunday, Haney said.

However, the system was functioning at reduced capacity, and officials did not know how long it would take to clear the huge backlog.

The cause of the shutdown was not known, and there was no estimate on when the system would be repaired, Fleming said.

Officials diverted seven incoming flights to an Ontario airport and advised international passengers departing Sunday to check the status of their flights before leaving for the airport.

Terminals that normally accept international passengers were full by 2:30 p.m. Saturday, and passengers arriving afterward had to remain on the runway until their was room inside the terminal buildings.

"This is just unbearable," said Gaynelle Jones, 57, who landed on a 13-hour flight from Hong Kong at about 2:15 p.m. and was still sitting on her plane five hours later. She said she had missed her connecting flight to Houston.

"We've already been on a plane for several hours, and they have no timeframe for when we'll be able to get off," Jones said during a cell phone interview.

Airport officials said the stranded planes were connected to ground power and passengers had access to food, water and bathrooms.

"People are getting a little stir-crazy, feeling claustrophobic," said Chris Cognac, 39, who was returning with family and friends — including 10 children — from a week in Puerto Vallarta. The group had been sitting on the tarmac for five hours when he spoke by phone.

Passengers on his plane were in the aisles, holding their carry-on luggage, and ready to disembark when the flight crew asked them to return to their seats, Cognac said.

"Everybody's pretty angry with customs at the moment because they're not informing any one of anything," Cognac said. "It's becoming a logistical issue with diapers."