OTTAWA — Canada on Wednesday tightened security at its airports, seaports and border crossings and reported scattered delays for commercial traffic entering the United States.

At mid-afternoon, there was a three-hour wait for trucks entering the U.S. at the Ambassador Bridge between Detroit and Windsor, Ontario, the world's busiest border crossing, and two hours at the Peace Bridge between Buffalo, N.Y. and Fort Erie, Ontario. There were minimal delays at the half-dozen other land border crossings, except for a one-hour wait for commercial traffic between Blaine, Wash. and Surrey, British Columbia on the West Coast.

Commercial traffic entering Canada from the United States encountered no delays save for a 30-minute wait at Blaine-Surrey. The Canada Customs and Revenue Agency monitors wait times daily, mornings and afternoons.

Canada Customs officers at all border crossings are in "a heightened state of alert," said Elinor Caplan, federal minister responsible for the Canada Customs and Revenue Agency. Goods and people crossing to the U.S by road, rail, air or water will be subject to "more intensive referral and searches," she said.

"Enhanced protection measures to strengthen our (Canada-U.S.) mutual security may include increased inspections, more detailed questioning, and more intensive document review," she said. "In addition, export checks to protect border infrastructure will be done in southern Ontario (at New York and Michigan crossings)."

"While we will make every effort to reduce the delays and minimize the effects of these measures, security will remain our prime objective," she said.

Canada had initiated random spot checks of vehicles leaving for the U.S., Deputy Prime Minister John Manley said. The U.S. requested the checks after raising its domestic terror alert level to orange on Feb. 7, he said, and now "we are doing so again. We will be responding over the next few days as the situation develops."

Officials at the Canadian Food Inspection Agency told JoC Online that the agency was tightening surveillance of food and agri-product import and export shipments.

By COURTNEY TOWER