Updated

Canada's ambassador predicted Monday that the United States would drop a controversial proposal that would require all travelers to show passports (search) in order to cross the long border between the neighboring nations.

Discussions with the Bush administration, which introduced guidelines to crack down on potential terrorist travel across borders, indicates that "passports will not be the ultimate requirements," Canadian Ambassador Frank McKenna (search) said in an interview with The Associated Press.

Currently, U.S. and Canadian travelers need only a driver's license to crothat both sides of the border think it would be a very damaging change. ... This would cause real havoc to the economy."

Canada is the largest U.S. trading partner, with $1.2 billion worth of goods crossing the border daily.

The Homeland Security and State departments proposed the rules two months ago to deter terrorists from entering the country. But a week later, President Bush stepped back from the plan, saying he was surprised to hear of it and feared it could hamper travel to the United States from neighboring countries.

McKenna also said he was taken aback to hear the plan when it was introduced April 5.

"We were considerably surprised," he said.