Two roadside bombs hit a Canadian military convoy just west of Kandahar on Friday, a day after the deaths of four soldiers raised questions about Canada's role in Afghanistan.

One of the bombs detonated between two vehicles, but there was no major damage and the convoy continued to drive through the danger zone.

One civilian vehicle was destroyed in the first explosion but it was unclear whether any civilians were injured.

The bombing occurred at 7:40 a.m. local time on Highway 1, just west of the Maywand District centre. The area, just west of Kandahar on the border with Helmand province, is a known Taliban stronghold.

A day earlier, four Canadian soldiers were killed and 10 wounded in attacks near Kandahar in the bloodiest day of fighting so far for Canadian troops in Afghanistan.

Sgt. Vaughn Ingram, Cpl. Bryce Jeffrey Keller and Pte. Kevin Dallaire of the Princess Patricia's Canadian Light Infantry based in Edmonton were killed Thursday when Taliban militants attacked soldiers with rocket-propelled grenades on the outskirts of Kandahar.

Earlier in the day, Cpl. Christopher Jonathan Reid of Truro, N.S., was killed near Kandahar when a roadside bomb exploded near his armoured vehicle. Six other Canadians were wounded on Thursday.

More troops deployed

In Canada, Gen. Rick Hillier saw off 140 soldiers, all from the Ontario-based Royal Canadian Regiment, who left CFB Trenton for a six-month deployment in Afghanistan.

"What I said was, this mission is worthwhile … and you are the right kind of folks to do it," the chief of defence staff told reporters.

"You have the right training, you have the leadership, you have the equipment, you have the preparation and you have the support to go out and do that mission."

"Lastly I said: I'm so proud of you. Proud of them for being the soldiers that they are for wearing our nation's uniform, for representing our country so well, for what they do as soldiers, and most importantly how they do it."

The departing soldiers are among 2,100 Canadian troops heading to Afghanistan this month to relieve most of the soldiers currently on duty.

In Kabul, Afghan President Hamid Karzai offered his condolences over the deaths of the four Canadian soldiers and thanked Canadians for helping bring stability to the violence-plagued country.

"We are very sorry for the loss of Canadian soldiers yesterday and we thank the international community for their continued attention to Afghanistan," Karzai said.

Deaths prompt political debate

The deaths prompted Liberal defence critic Ujjal Dosanjh to accuse Prime Minister Stephen Harper of distorting and changing the scope of the mission in Afghanistan.

"I think Canadians believed that the focus of this mission is different than what it appears to be today — today it appears to be solely combat," Dosanjh said Thursday.

Dosanjh said the mission his party supported was one based on reconstructing a country destroyed by the Taliban. He said the mission's original mandate was development, diplomacy and defence.

"Combat is important, but winning the battle in hearts and minds [is] equally important," he said.

Harper insisted it's only through combat missions that Afghanistan will eventually be at peace, and continued to pledge his support for the military campaign.

"What the men and women in harm's way want and need to know at moments like this is that the government and Canadians stand behind their mission," Harper said.

"Through good times and bad, this government will honour their sacrifice. We will stand behind their mission and we are proud of the work that they are doing.

"They are in a leadership role … in the toughest part of that country facing the terrorist threat directly and helping Afghans rebuild their lives and communities."

With files from the Canadian Press