New security rules went into effect at U.S. borders on Thursday but did not cause the delays or confusion many expected.

Canadians who arrived at the border without proper documentation were allowed across with a warning and were given flyers reminding them for next time.

The , which apply to anyone crossing the border, require travellers prove their citizenship through specific documentation.

"The old days of a verbal declaration, due to security concerns and also to facilitate things, just doesn't exist any more," Chief Michael McMullen, chief inspector for U.S. Customs and Border Protection, told Â鶹´«Ã½ on Thursday.

Canadians crossing into the U.S. by land and sea will now need to provide a driver's licence along with proof of citizenship.

For most, that will mean providing a birth certificate or citizenship card at the border in addition to their licence.

Passports or a card from a trusted traveller program like NEXUS or FAST are acceptable, but not yet required.

Children under 16, as well as teens aged 18 and under travelling in school, cultural and sports groups, will need certified copies of their birth certificates.

Jim and Shelia Froats were two travellers surprised by the new rules.

"We don't have two pieces of ID, so we'll see what happens," Jim Froats told Â鶹´«Ã½ as they approached the border crossing near Cornwall, Ont. But, like others caught unprepared, the Froats were offered a warning and allowed across the border.

Customs officials across the country said delays were minimal and that most travellers were already carrying the documentation they needed.

McMullen told Â鶹´«Ã½ that 80 per cent of people crossing the Champlain, N.Y., border were already using passports.

He said along with providing better security, the new requirements will speed up traffic congestion at border crossings.

"Another important issue is facilitation. Because when people have these types of documents we can process them on primary much faster and reduce the delays and wait times at the border," he said.

At the Ambassador Bridge crossing into Detroit, the bottleneck traffic often seen by truck driver Paul Kraus was missing. "It's actually slow today," he told The Associated Press. Kraus, 42, said he always travels with his passport.

Many people were already under the impression that passports were a requirement after security tightened following the Sept. 11 attacks.

Officials had originally hoped to make passports mandatory by the end of January.

However, the U.S. postponed the date as concerns were raised that the new measures could stifle cross-border shopping.

According to the Western Hemisphere Travel Initiative, passports will become a requirement for Canadians travelling by land in June, 2009.

Canadians travelling by air are already required to have a passport.

With files from The Associated Press and a report from CTV Ottawa's Joanne Schnurr