A Canadian soldier has died in Afghanistan after insurgents attacked a remote outpost in the volatile Panjwaii district. It's the second death in three days.

Master Cpl. Erin Doyle was killed early Monday in the attack. He was a member of the 3rd battalion of the Princess Patricia's Canadian Light Infantry, based out of Edmonton.

Up to 10 gunmen attacked the outpost before dawn. Canadian soldiers returned fire and called in artillery and air support, killing or wounding all of the insurgents.

"Master Cpl. Doyle was killed while he was protecting his position and his fellow soldiers," task force commander Brig.-Gen. Denis Thompson told reporters.

It was the third tour Doyle had served in Afghanistan.

"Erin was a big, tough, mountain of a man who enjoyed the outdoors," said Thompson. "He was a true warrior and just the person you would want beside you in a firefight."

Friends described the 200-lb. man as a "friendly giant." Chief Warrant Officer Chris White knew Doyle for five years, and said he was the kind of guy you want to "sit down and have a beer with."

Doyle leaves behind his wife Nicole and daughter Zarine.

Prime Minister Stephen Harper released a statement Monday saying Doyle was an exceptional and courageous soldier.

A second soldier was injured and taken to the multinational hospital at Kandahar Airfield, where the bulk of Canada's troops are based.

The attack happened at a small outpost beyond the forward operating bases in Kandahar province, according to the Globe and Mail's Gloria Galloway, who is currently reporting from Kandahar Airfield.

She told CTV Newsnet that soldiers have been "devastated" by the loss of two comrades in a span of just three days. Doyle is the 90th Canadian soldier to die in Afghanistan since 2002.

Last weekend, Master Cpl. Josh Roberts was killed during another firefight with insurgents. A convoy of Afghan civilian security personnel was travelling through the area at the time, and the Canadian military is investigating any possibility of friendly fire.

Canadian and U.S. soldiers are interviewing members of two private security forces who were in the convoy. The two groups are called Compass and USPI.

"Their normal contact drill is as soon as they get hit with something, it's 360 -- open up on everything that moves," Canadian soldier Maj. Corey Frederickson told Stars and Stripes, the overseas newspaper for the U.S. Armed Forces. "That's probably what happened. And in the meantime, we think maybe a coalition soldier got hit."

In video footage shot by Stars and Stripes, U.S. soldiers ask members of USPI and Compass whether they fired any ammunition during the incident. When one man says no, a soldier accuses the group of lying.

The soldiers then search vehicles operated by members of USPI and Compass, and find unauthorized heavy weapons and police uniforms.

"The Compass convoy is the one we suspect opened up on the Canadians," U.S. Army Maj. Kevin J. Reilly told the newspaper.

The Canadian military is still investigating the incident and no reports of friendly fire have been confirmed.

Canadian military officials have said private security teams are essential for keeping security in Kandahar, especially in turbulent regions like the Panjwaii and Zhari districts.

With files from The Canadian Press