Two Canadian soldiers in Afghanistan have been wounded in a suicide bombing -- just hours after four others were hurt when their vehicle was struck by a roadside bomb.

In the most recent attack, the troops were returning from a patrol in a light-armoured vehicle when they were hit by the attacker's car at around 7:30 p.m. Wednesday in Kandahar City, said coalition spokesman Maj. Quentin Innis.

The attacker was killed and two Canadian soldiers were injured, he said.

CTV's Steve Chao reported that one Canadian soldier was seriously injured, but the injuries are not life-threatening. The other soldier had minor injuries.

An Afghan bystander was also killed and seven others, including a policeman and six civilians, were injured.

In the earlier attack, four Canadian soldiers were wounded -- one seriously -- after their armoured vehicle hit a roadside bomb north of Kandahar City.

The LAV 3 was returning from a resupply mission when it was hit near a forward base at Gumbad, 75 kilometres north of Kandahar City.

Major Mario Couture, a spokesman for the Canadian-led coalition, told reporters the soldiers were airlifted to the coalition hospital at Kandahar airfield where three of them were listed in good condition.

Two men were captured following the blast and were handed over to Afghan government authorities, military officials said.

The identities of the wounded have not been released.

These are the first Canadian casualties since Operation Mountain Thrust was officially launched last Wednesday, although two Canadians were wounded in a battle with insurgents west of Kandahar City on June 12 .

Operation Mountain Thrust

Operation Mountain Thrust marks the largest deployment yet for a single mission in Afghanistan.

Around 7,000 coalition combat soldiers are involved in the operation to root out Taliban in Kandahar, Helmand, Zabul and Uruzgan provinces.

Couture said the coalition is doing all that it can to mitigate the risks to its soldiers involved in resupply missions.

"We adapt to threats, we use several types of vehicles, we are using the best equipment that we can,'' he said. "We vary our routes but unfortunately we cannot mitigate the risk to zero,'' he said.

Wednesday's attacks have prompted questions about the Canadian Forces lack of transport helicopters in Afghanistan to handle resupply missions.

The Edmonton-based Princess Patricia's Canadian Light Infantry battle group relies almost solely on vehicle resupply convoys that mainly use roads or dried riverbeds.

Couture acknowledged having helicopters, such as big, twin-rotor Chinooks, would help, but he also said was important for coalition forces to have a strong presence on the ground.

"If you are going to bring supplies, if you are going to carry troops into zones of operation, the Chinook might be the best tool that you can have,'' he told reporters.

"But if you want to maintain presence, if you want to be visible by locals and the enemy, then the best way is to be visible on the ground."

The Canadian Forces once had a force of Boeing Chinooks, but Ottawa sold them to the Netherlands in the early 1990s.

Defence analysts say the lack of such an airlift capability is a big problem.

"We'd have less need for roadbound convoys if we had the Chinook. Plain and simple," David Bercuson, a professor at the University of Calgary's Centre for Military and Strategic Studies, told the Canadian Press.

"We disposed of our Chinooks about ten years ago; there's no way to get any quickly. But since we'll be there for another three years, the quicker the better!"

With files from the Canadian Press