SAN YSIDRO, Calif. -- The wait for those seeking to cross into the U.S. at the Mexican border was longer Monday as inspectors checked travelers for a new type of border-cross card.

BORDER TRAFFIC Check delays at the Calif.-Mexico border Check San Diego traffic

Lengthy border waits have become a staple at the U.S.-Mexico border since heightened security measures were put in place following the Sept. 11 terrorist attacks.

Beginning Monday, Mexican nationals entering the U.S. at San Diego and other ports of entry are required to present a new border crossing card that carries a photo and machine-readable information.

The new Biometric Crossing Cards, also called "laser visas," were mandated long before the recent attacks on the World Trade Center and the Pentagon. The cards are a requirement of the Illegal Immigration Reform and Immigrant Responsibility Act of 1996.

The procedure for applying for the BCC has been in place since 1998, according to Immigration and Naturalization Service officials. About 4 million of the new cards have been issued since then.

The permits -- a staple of border life from Brownsville, Texas, to San Diego -- allow Mexicans living near the border to come north to shop, visit relatives or see a doctor.

The new cards, which are valid for 10 years, are more secure and harder to counterfeit, according to the INS.

Those who have applied for the new cards (pictured, left) but have not yet received them will still be allowed to cross the border with their old cards as long as they have a valid approval sticker, which currently expires on Dec. 31, 2001, INS officials said.

INS officials say that border inspectors will turn away those with outdated travel documents, except in cases of emergency.

It was unclear how many people still carry the old card. When Congress first mandated the change to laser visas in 1996, an estimated 5.5 million old cards were in circulation.

Conceivably, checking for the new documents and turning away those who are not eligible for entry could add considerably to delays at the border which have been averaging one or two hours since Sept. 11.

It is possible that Congress will extend the deadline for obtaining the new visas.