SAN DIEGO -- Pedestrians older than 14 must show identification while crossing the U.S.-Mexico border in California and Arizona, officials with the Immigration and Naturalization Service said Wednesday.

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Bring Your I.D. And Expect Delays Border Crossers Not Happy With Security

The new security measure, effective immediately, is expected to result in lengthy delays at border crossings.

It will permit immigration inspectors to use a nationwide law enforcement database to check the names of all border crossers for any arrest warrants, INS spokeswoman Virginia Kice said.

The ID checks are one in a series of new security measures at the U.S-Mexico border following the Sept. 11 terrorist attacks.

Until now, U.S. citizens had not been required to show identification when returning from Mexico and inspectors only conducted database checks on those deemed suspicious.

Inspectors began requiring IDs from pedestrians in Texas and New Mexico, but delayed the step in California and Arizona as local INS officials sought to clarify details.

The program is expected to have the biggest effect at the San Ysidro Port of Entry in San Diego, the world's busiest border crossing, where more than 30,000 pedestrians cross each day.

"We definitely anticipate there will be additional delays," Kice said. "We don't know yet how significant they will be."

Kice said everyone except very young children must have identification. Penalties for not carrying identification will be decided on a case-by-case basis.

Inspectors will detain anyone with an active felony arrest warrant and hold them if the police agency seeking them requests it.

The union representing INS inspectors in San Diego welcomed the new policy as an additional security measure that will help to catch wanted fugitives and protect the nation's borders.

"The more checks we do, the safer I feel," said Eric West, the president of Local 2805 of the American Federation of Government Employees.

The union local's vice president, Tim Moroney, said he has received complaints from inspectors that INS management has discouraged them from conducting database checks on all pedestrians because it would slow traffic at the already heavily congested border crossing.

"Officers now feel good about doing our job," Moroney said.

Those who cross in vehicle lanes may also be asked to show identification but authorities said there are no immediate plans to require U.S. drivers to show ID.