The Taliban quickly claimed responsibility for the explosion, the deadliest single attack on the NATO coalition since April when a similar bombing killed another six Canadians.
"Clearly, they have managed to kill six great young Canadians today which is an absolute tragedy," Brigadier-General Tim Grant told a televised news conference in Kandahar.
According to Grant's briefing, the attack occurred as the soldiers were returning as part of a 12-vehicle convoy from a joint operation with Afghan forces. He said his forces would investigate the attack and decide if the Canadian troops will change their tactics in the wake of the losses.
"As with every attack we will look at what has happened and will decide at that time if there is something we need to do to increase the protection for our soldiers," said Grant.
Wednesday's assault came less than 24 hours after another ambush near Khandahar that killed seven Afghan police officers.
The bombing brings to at least 102 the number of foreign soldiers that have been killed in Afghanistan this year, including at least 46 Americans, 18 Britons and 22 Canadians.
The attacks have made relations between the NATO forces and Afghan civilians increasingly tense. On Tuesday, coalition forces said they had opened fire on a motorcyclist who approached them in a "threatening manner", killing the suspect. But civilian witnesses said the soldiers fired indiscriminately, injuring many civilians and killing at least one.
That shooting was just the latest in the drumbeat of condemnation by local and regional leaders who say the allied campaign against Taliban insurgents has taken a heavy toll on innocent civilians.
Last weekend, in one of the reportedly bloodier incidents, local Afghan officials told The New York Times that dozens of civilians, and perhaps a great many more, were killed during United States-led airstrikes in the neighboring province of Helmand.
"We have received differing numbers of the civilian and the militants' casualties," the mayor of Grishk, Dor Ali Shah, said. "We sent delegates to the site, but the area was surrounded by coalition forces. Some sources tell us the number of civilian dead is 120, others say 60, others say 35. We are actually mixed up, so we will wait to confirm."
The mayor said the bombardment came after insurgent forces attacked NATO ground forces near the town earlier in the day.
According to military officials the lack of NATO forces has made the job of minimizing civilian casualties more difficult.
"Our forces are stretched to the limit," Bruno Kasdorf, chief of staff of the NATO forces in Afghanistan said Wednesday, according to Reuters.
"[W]ith more forces and means we could establish more accurately where the enemy is and also proceed more accurately with the deployment of weapons," Kasdorf said.
Southern Afghanistan has seen fierce fighting in the past several weeks. More than 2,900 people -- mostly militants -- have been killed in insurgency-related violence in Afghanistan this year, according to an Associated Press tally of numbers provided by Western and Afghan officials.