Prime Minister Jean Chretien is calling the two Canadian soldiers killed in Afghanistan heroes and is extending his condolences to their families.

Chretien spoke with reporters as he arrived at Vancouver International Airport Thursday afternoon. He said the soldiers who lost their lives "have to be honoured as heroes" and prayed that those injured would have a speedy recovery.

The prime minister said it was his understanding that the explosion was caused by a landmine, but added that information was still being collected and no one had all the facts.

"We are not aware of the exact causes at this time and we will keep you informed as we receive information."

The prime minister said that those who lost their lives were fighting against terrorism in Afghanistan. He added that no one is immune from terrorism and it can appear in any country or city.

"We made a commitment that they (Canadian troops) will be there for a year with 2,000 people and they will carry on bravely with their duty," Chretien said.

When news of the deaths broke, the prime minister was en route to Vancouver and he issued a statement.

"I was deeply saddened to learn that brave Canadian soldiers had been killed and wounded in the line of duty in Afghanistan ... The news today is a painful reminder that defending our values and doing our duty can come with a very high price," the statement said.

The anguish of military families was reflected in the words of Maureen Decaire in Winnipeg. Her son Brian was one of the soldiers wounded in the friendly-fire incident in Afghanistan last year.

"Oh God, it's awful, those poor people. ... It is very, very, very hard to have your family members hurt when they are so far away and not to know the extent of their injuries. For the families who had someone killed, I can't imagine what they are going through. I just feel ill about it," Decaire said.

Barb Stirling, the wife of one of the injured soldiers, said she was only told that her husband, Cpl. Thomas Stirling, had sustained burns and required minor surgery.

"That was pretty much about it. They didn't tell me how severe the burns were, how minor they were, or what the surgery was," Stirling told CTV Newsnet.

Sterling said the military has promised it will try to keep her as up to date as possible. She said she was still in shock and started the day thinking she would be meeting her husband online.

"We were to meet this morning on the computer, and he wasn't there. I just assumed it was problems with their Internet services, as it usually is," Stirling said.

When asked how she felt about the Defence Minister John McCallum's comment that Canada's commitment to the mission was still strong, she said she agreed.

"They're out there to do a job, and that's what they want to do, so all the power to them...I'm sure they're feeling their loss, but they've got to go on and do the job the military tells them to do," Stirling said.

Like the prime minister, Canadian Alliance Leader Stephen Harper said the country was proud of its military and the sacrifices they have made.

"The Canadian Forces have always served our country bravely and with honour. They continue that proud tradition around the world today, including in Afghanistan," Harper said.

"Today, when two of our soldiers have made the ultimate sacrifice, we honour their bravery. We grieve for them, and we pledge that we will never forget them," he added.

McCallum told the House of Commons the incident was "a price to pay for helping others."

"But it remains our duty to protect the Afghan people. But even though we knew that our soldiers were in harm's way, it does not lessen our shock as we try to absorb this terrible news. It is a painful reminder that defending our values and doing our duty as a nation can come with a very high price," McCallum said.

The defence ministry named the dead soldiers as Sgt. Robert Alan Short, 42, and Cpl. Robbie Christopher Beerenfenger, 29.

Short, an experienced light engineer known as a pioneer, was the father of two children. Beerenfenger, who had been seconded from a mechanized battalion, was the father of four children.

Stirling was the driver of the lead vehicle and his condition is listed as stable. Master Cpl. Jason Cory Hamilton, Cpl. Cameron Lee Laidlaw were slightly injured in the incident.

All are members of the Royal Canadian Regiment, 3rd battalion, based in Petawawa, Ont., but their home towns were not immediately known.