WINDSOR, Ontario - Canada unveiled a major border-security and prosperity initiative yesterday, saying it would spend more than $368 million over the next five years to protect its border from terrorist, economic and environmental threats.

Public Safety Minister Stockwell Day made the announcement at the Canada-U.S. border crossing between Windsor and Detroit, where one-third of the $1.6 billion in daily trade between the North American neighbors passes.

"I even sometimes surprise my American friends when I remind them that the trade that comes across the Ambassador Bridge in total is greater than all of the trade that exists between the United States and Japan," Day said at a news conference.

Security experts have long criticized the lack of security measures along Canada's side of the 4,000-mile border with the United States, particularly since the Sept. 11 attacks.

Conservative Prime Minister Stephen Harper pledged when he was elected nearly a year ago to strengthen the frontier between the world's largest trading partners, including the new security measures, and eventually arming Canada's border guards.

The bulk of the money, $337 million, is for an electronic manifest program, which will allow computer-automated risk assessments of cargo shipments before they reach Canada.

The 18,000 trucks that cross the U.S.-Canada border each day, as well as all railroad, air and marine cargo carriers, will eventually be required to file electronic manifests before their shipments arrive.

This will allow border-service agents to determine in advance whether the cargo, or those who deliver it, should be further screened.

The program was developed in cooperation with the U.S. Department of Homeland Security and is part of the Security and Prosperity Partnership of North America, launched in 2005 by then-Prime Minister Paul Martin, President Bush, and then-Mexican President Vicente Fox.

Day would not say when the electronic manifests would become mandatory at the 119 border crossings.