More than 500 army troops, backed by helicopters, armoured vehicles and artillery, will turn downtown Winnipeg into an armed camp as part of a military exercise to train soldiers for the modern battlefield.

Exercise Charging Bison will unfold for seven days and nights beginning April 30 next year in what is believed to be the largest urban warfare training exercise of its kind ever held in Canada.

There won't be live ammunition, but there will be laser weapons and a variety of blanks and 'simunition' -- or simulated munitions -- that make noise and smoke or discharge harmless projectiles.

The drill is designed to simulate the kind of complex conditions soldiers would encounter in places such as Afghanistan and Iraq, where conventional warfare is conducted simultaneously with humanitarian relief operations and nation-building, said Col. Kelly Woiden, commander of 38 Brigade.

The mission

What: Operation Charging Bison will involve 500 troops training in downtown Winnipeg.

Who: The operation is run by 38 Brigade.

Why: It’s designed to train troops in urban warfare.

Where: A base camp will be set up on the western edge of the city, but most of the exercises will take place in the downtown.

When: Day and night between April 30 and May 6.

Urban battlefields are sometimes known as "three-block wars" because troops could help people on one block, fight insurgents on another, and guard convoys on another, Woiden explained.

"We're going to create a realistic environment of the situation that individual soldiers can face today," he said. "You could be doing humanitarian relief one moment and then fighting a war the next. It is the most complicated terrain for a soldier."

The operation is also part of a long-term plan to prepare 200 of the brigade's soldiers to support a 1,000-person task force in 2008, if necessary, he said.

The 38 Brigade is a reserve unit responsible for a dozen formations in Saskatchewan, Manitoba and northwestern Ontario.

It will provide most of the personnel for the exercise, although some will come from British Columbia and Alberta, and possibly from the United States, Woiden said, adding 17 Wing will also provide logistics support.

About 100 police officers and civilians will be given a role in the exercise, either as opposing forces or relief organizations.

The military may also recruit drama students from the University of Manitoba to play the roles of demonstrators or insurgents.

"The purpose is to learn and we may rerun the same scenario several times," Woiden said.

The operation will occupy a large swath of downtown Winnipeg from Balmoral Street on the west, south to the Assiniboine River, north to the CP Rail tracks and east into The Forks and St. Boniface.

Woiden said the exercise is still in the planning stages and the boundaries could change. A base camp will be established on the western edge of the city, but there will be smaller camps downtown, he said.

The exercise will continue night and day, but Woiden said he did not anticipate any significant disruption of traffic or commercial operations.

Military observers will keep score and determine who was killed and who was wounded during the exercise.

"This is different than traditional training when the infantry were facing open ground in front of them, with soldiers in a different uniform," Woiden said. "This is much more complex because we don't know who the enemy is or where the threats are."

Reserve units have been used in the past to fill out the ranks of the regular force, but Woiden said the military now wants the militia trained to higher level of combat readiness.