The Canadian military has released the names of five of the six Canadian soldiers killed Sunday in Afghanistan in a devastating roadside bombing.

They are Sgt. Donald Lucas, 31, of Burton, N.B.; Cpl. Christopher Paul Stannix (reservist), 24, of Dartmouth, N.S.; Cpl. Aaron E. Williams, 23, of Lincoln, N.B.; Pte. Kevin Vincent Kennedy, 20, of St. Lawrence, Nfld.; and Pte. David Robert Greenslade, 20, of Saint John, N.B.. The family of a sixth man requested that his name be withheld.

Five of the dead soldiers are members of the Royal Canadian Regiment, 2nd Battalion, based at CFB Gagetown in New Brunswick. Stannix is with the Halifax-based Princess Louise Fusiliers.

Two of the dead men are fathers.

The event is described as the single largest one-day death toll suffered by Canadian troops since the Afghanistan campaign began in 2002.

The soldiers were killed early Sunday afternoon local time.  An apparent improvised explosive device detonated, striking their LAV-III armoured vehicle as they guarded a convoy about 75 kilometres west of Kandahar. The location is near the boundary between Kandahar and Helmand provinces.

CTV's Paul Workman reported from Kandahar that the soldiers from Hotel Company, who had been outside the wire for about a month, had been travelling the same route for the past couple of days. "It's possible the makeshift bomb was buried overnight at or near the same place."

Back at the main base in Kandahar, other soldiers had been opening Easter gift baskets from their families back home. The base's flags were lowered to half-mast when news of the tragedy emerged.

"This is a tough time ... We've lost six of our best and really, we're thinking of the families," Col. Mike Cessford, acting commander of Task Force Afghanistan, told reporters in Kandahar.

Cessford said two other soldiers were evacuated to the NATO medical facility in Kandahar for treatment after the attack.

One of them had serious abdominal injuries and would likely be transferred to the U.S. hospital in Landstuhl, Germany, for treatment. Another soldier received minor injuries.

There were 10 soldiers in the vehicle. Cessford said he had spoken to the two uninjured soldiers and said they were shocked by the deaths of their comrades.

"They were quiet, as you can appreciate. They were full of thoughts, they were grateful for the comradeship they had, they were grateful for the friendship they had, and I think they were grateful the family had rallied around them at this point."

Despite the pain of the loss, Cessford said the mission would continue.

"Clearly this is a very disturbing even to the military family, but the mission will go on, that's what we do, and we do it to help the people of Afghanistan, for all the little kids who wave at us every day."

An investigation has been launched to determine how one bomb could have killed so many soldiers inside one of the army's best armoured vehicles.

"Our sources here are telling us that there was quite a bit of extra ammunition stacked inside the vehicle. That's pretty normal," Workman said.

"And when the bomb went off, so did some of the ammunition. And that's why such a large number of soldiers died. But that has been not been confirmed, and we have to remember that for now."

Workman had earlier interviewed Col. Rob Walker, the battle group's commander, about his group's success in tracking down roadside bombers.

 "We've killed or captured a number of individuals and we've had no mines or anything for at least a week now," Walker said.

Workman had been out on with the soldiers on Saturday night, leaving just hours before the blast. "As you can imagine, it was quite a shock to learn the soldiers I'd shared a campsite with were dead," he said.

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Prime Minister Stephen Harper spoke in France, where he is attending ceremonies marking the 90th anniversary of the Battle of Vimy Ridge.

"Sadly today has been a difficult day in Afghanistan," Harper said at a dinner for veterans in the French city of Lille.

"We've learned that an incident has claimed the lives of six Canadian soldiers and injured a number of others."

"Our hearts ache for them and their families, and I know as we gather here on Easter Sunday our thoughts and prayers are with them," he said.

Harper was the first to report the news.

Since 2002, 51 Canadian soldiers and one diplomat have been killed in Afghanistan, including Sunday's deaths. There are roughly 2,500 Canadian troops serving in the country, the majority of them stationed in the volatile southern regions.

However, Canada had not suffered any combat deaths so far this year. The last two occurred in November 2006, when Chief Warrant Officer Bobby Girouard and Cpl. Albert Storm died in a suicide bombing attack outside Kandahar City.

Earlier attack

Earlier Sunday, a NATO official confirmed that one soldier was killed and two others were wounded when a roadside bomb exploded in southern Afghanistan, an official said Sunday.

No details were released about the names or nationalities of the soldiers, or even where the deadly attack took place.

In another Sunday attack, in Nangarhar province in eastern Afghanistan, a suicide attacker detonated his car bomb next to a U.S.-led coalition convoy.

And in eastern Khost province, a gunman riding on the back of a motorcycle fired on Afghans who were working for ISAF. Two Afghans were killed and another was wounded, ISAF confirmed.

Violence follows NATO success

The violence came after NATO retook Sangin district in Helmand province in the south.

The region is considered one of the world's foremost opium growing areas, and has long been held by the Taliban.

About 1,000 NATO and Afghan troops were involved in the operation which began late Wednesday as part of Operation Achilles -- NATO's largest offensive yet in Afghanistan, involving 4,500 NATO and 1,000 Afghan troops.

The campaign is designed to push Taliban militants out of the northern tip of Helmand province.

Anticipating the operation, Taliban fighters and foreign militants have streamed into the area, U.S. and NATO officials claim.

With a report from CTV's Paul Workman and files from The Canadian Press