A federal official says new rules for the types of identification U.S. or Canadian citizens must present to cross into the country shouldn't cause significant delays and won't be strictly enforced at first.
Jayson Ahern, deputy commissioner with U.S. Customs and Border Protection, says officers will have latitude to admit people who are unaware of the changes once their identities are confirmed.
Ahern is heading a national effort to call attention to the changes.
Under the rules going into effect today, people will no longer be allowed to simply declare to immigration officers at border crossings that they are citizens.
Instead, those 19 and older will have to show proof of citizenship -- a passport, trusted traveler card or a birth certificate and government-issued ID such as a driver's license.
Some businesses and lawmakers worry that new ID requirements could create widespread confusion and delays and discourage some people from making the trip.