CANCUN, Mexico — U.S. President George W. Bush says he won’t oppose Congress’s law requiring anyone entering the U.S. to carry a passport or similar biometric credentials even though businesses on both sides of the border insist the rule will hamper travel and trade.

Speaking along side Canadian PM Stephen Harper and Mexican President Vicente Fox at a NAFTA summit in Cancun last week, Bush acknowledged the rule could cause trouble for some businesses, but confirmed the U.S. won’t back off from the plan.

Under the requirement, which takes effect in 2007 for land crossings and by the end of this year for air and sea travelers, Canadians, and U.S. citizens returning home, must show a passport to U.S. Customs officials every time they cross the border.

Only 20 percent of Americans reportedly have passports.

Earlier this year, the Bush Administration said it would consider introducing a newer, less expensive, biometric identity card that would be accepted as a substitute for a passport.

Harper said that the passport rule is a reality Canadians will have to get used to. “People finding they don’t have documentation whether it’s for business or for ordinary travel, they’re going to find they do in fact need it in the future,” he said at a news conference.

The American Trucking Association has been lobbying the Administration to exempt truck drivers from the passport rule. Both the ATA and the Canadian Trucking Alliance are urging the government to consider existing federal credentials in lieu of passports, such as Free and Secure Trade (FAST) IDs, the Transportation Worker Identification Credential (TWIC), and other appropriate government issued identifications and screening programs.

— with files from Canadian Press