Border officials are reminding travelers that beginning June 1, all adult U.S. citizens will need a passport to cross the border into Mexico or Canada.

U.S. citizens can now cross the border using a birth certificate coupled with a government-issued identity card that has a photo, such as a driver's license. That will end next month.

U.S. Customs and Border Protection officers at the border have been handing out fliers explaining the new rules.

The agency will hold two passport fairs in South Bay later this week where people can apply for passports or the new passport cards, said Vince Bond, a spokesman for Customs and Border Protection in San Diego.

The agency is urging frequent travelers to get the new passport card, because the card has a radio chip that displays a person's information automatically via computer when his or her car approaches the border inspector.

"Our anticipation is that it will speed up the process, because the officer will already have the information there on the screen," Bond said.

Officials say getting Americans to use passports also will improve border security.

The requirement is part of a 2004 law passed by Congress called the Western Hemisphere Travel Initiative.

The law, enacted in reaction to the Sept. 11 attacks, was designed to "get control" of the borders by verifying the citizenship and identity of everyone entering the U.S. by land, sea or air from Canada, Mexico and the Caribbean.

Children 16 years old and younger will still be able to use their U.S. birth certificates as proof of citizenship.

Calls to postpone the rules were rebuffed by the Obama administration.

"We are on track to implement the (new rules) on June 1 of this year at our land and sea ports of entry," Department of Homeland Security Secretary Janet Napolitano told Congress earlier this month.

Bond said customs officers will have "enforcement discretion" when people do not have a passport or another similar document.

U.S. citizens who do not have a passport will not be denied entry, but may be subject to further scrutiny to verify their citizenship, Bond said.

If a citizen has applied for a passport or passport card but has not received the document, he or she may show the receipt, along with other documents, such as a California driver's license, to enter the country, Bond said.

Merchants in Mexico, whose businesses have been hurt by the recent lack of tourism, say they are concerned that the new requirement might further discourage travel south of the border.

Rosarito Beach Mayor Hugo Torres, who also is owner of the historical Rosarito Beach Hotel, expressed some optimism about the change.

"We hope that the transition goes smoothly and that the new procedures do indeed make the border crossing more efficient for our visitors and others who use it," said Torres, whose seaside city relies heavily on U.S. tourists for revenue.

The new rules will not change document requirements for noncitizens, such as immigrants who have permanent resident cards, also known as green cards.

People with frequent-traveler cards, known as Nexus, Sentri and Fast, may also continue to use them.

U.S. military cards will be accepted only when traveling on official orders.

Otherwise, military personnel must carry a passport just like everyone else, officials said.

For more information, visit www.travel.state.gov or www.getyouhome.gov.

Contact staff writer Edward Sifuentes at 760-740-3511.

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