The United States has set tougher identification rules for U.S. and Canadian citizens who want to enter the country from Canada.
Starting Thursday, travelers 19 years of age or older will no longer be able to cross into the United States by land or sea by simply stating their identity or citizenship.
The U.S. Department of Homeland Security now requires documented proof.
Travelers must produce a passport, trusted traveler card or a government-issued identification card, such as a driver's license.
Travelers who do not have the proper identification may be delayed, as border officers try to verify their identity and citizenship.
Authorities say border officers will have some latitude to admit people who are unaware of the new rule.
The agency will provide a grace period for travelers without the proper identification and hand out fliers explaining the change.
Mexican citizens will continue to have to present valid passports and visas.
Canadian citizens previously were not required to show a passport but will need one starting next year.
Some information for this report was provided by AP.