from exploiting the relative ease of travel in North America, means that Americans who lack U.S. passports will have to obtain them to travel between the United States and neighboring nations. It also will require Mexicans and Canadians to present either passports or another official document to enter this country, with details to be determined.

Currently, U.S. citizens in most cases need to show only driver's licenses to reenter this country from Mexico and Canada, though officials said that since the Sept. 11, 2001, attacks, some officials at border crossings at times have asked for additional documents.

";We're asking people to think of travel in and out of the U.S. [in this hemisphere] in the same way they would travel to and from Europe,"; said Elaine K. Dezenski, deputy assistant secretary for border and transportation security at the Department of Homeland Security.

Some travel industry executives predicted that the initiative could lead to long lines for foreigners entering this country and could discourage U.S. youngsters from traveling on school trips, or spontaneously, to Canada and Mexico. Much smaller percentages of young people have passports than older people do, industry officials said.

An increasing amount of travel planning is being done only days or weeks before a vacation begins because of Americans' harried lifestyles, and the new rules could discourage U.S. citizens without passports from taking quick jaunts to Canada and Mexico, tourism officials said.

";For the last-minute traveler, this could be a problem,"; said Hank Phillips, president of the National Tour Association, which represents the tourism industry. ";We're concerned about this, but we're taking a wait-and-see attitude, because security is a top priority.";

Michael Palmer, executive director of the Student & Youth Travel Association, which represents tour operators, said yesterday that the new rules also could ";drastically"; reduce the number of Mexican and Canadian students who visit the United States.

";I can see the student travel business [from Canada into the United States] almost drying up,"; said Doug Ellison, who owns a large youth travel firm outside Ontario. The regulations also will discourage Canadian cross-border shoppers, he said. ";If you don't want us to come, you're giving us a good reason not to,"; he said.

The changes, to be phased in over the next three years, were mandated by the intelligence reform law approved last December and have been expected for months.

Sixty million Americans have U.S. passports, and officials expect to issue 10 million more this year. More citizens are obtaining passports every year because of the perceived desirability of having citizenship documents, said Maura Harty, assistant secretary of state for consular affairs.

The new policy was needed to tighten security for travelers around the Western Hemisphere in part because of heightened concern that terrorists could smuggle equipment or operatives into the United States from neighboring countries, officials said. U.S. officials also want to reduce their reliance on state driver's licenses because of the ease of obtaining fraudulent licenses.

State and Homeland Security officials are distributing cards to U.S. and foreign travelers in this hemisphere, warning that ";all travelers to and from the Americas, the Caribbean and Bermuda will soon be required to have a passport or other accepted document that establishes the bearer's identity and nationality to enter or reenter the United States.";

The rule's first phase will go into effect December 31, 2005, requiring all U.S. citizens traveling by air or sea to or from the Caribbean, as well as Central and South America, to have passports. The next phase, which will apply these rules to all air and sea travel to or from Mexico and Canada, will begin a year later.

The last phase, which will affect the most people by far, will take effect on Dec. 31, 2007, and will apply the requirement to all air, sea and land border crossings with Mexico and Canada.

Phillips of the National Tour Association predicted long lines at land border crossings in the first months after that, however thorough the planning, because the vast majority of the 1.1 million people entering the United States every day come by land.

U.S. officials said they will decide later whether to accept as valid entry documents a number of types of official papers used by some Mexicans and Canadians who cross into this country frequently. Among these are the border crossing card and the Secure Electronic Network for Travelers Rapid Inspection (SENTRI) card, given to some Mexicans; and other papers given to some Canadians under the Free and Secure Trade (FAST) and Nexus frequent-visitor programs.

--------------------------------------------------------------------------------