A male passenger in an Afghan vehicle died after Canadian soldiers fired on a civilian truck that was driving toward their military convoy Thursday evening.

The soldiers were travelling through Kandahar City at about 8:30 p.m. when the transport truck loaded with fruit approached their convoy, said military officials.

Soldiers in the convoy, fearing a suicide attack, tried repeatedly to get the driver to turn away before eventually firing a warning shot, said officials.

"Neither the warning signals nor the warning shot were heeded," said military spokesman Lt. Alain Blondin.

The soldiers then fired two additional shots from the turret cannon on a light-armoured vehicle, stopping the truck, and a subsequent investigation revealed one of the occupants was killed.

The soldiers had followed proper escalation of force procedures, said Blondin.

"Our soldiers are trained to take all appropriate steps to minimize civilian casualties. However, they must take action to protect themselves when they believe they are being threatened."

International forces stationed in Afghanistan have warned Afghan drivers not to approach military convoys lest they be mistaken as suicide bombers.

The shooting is under investigation by Canadian and Afghan officials.

Canadian soldiers cleared of wrongdoing in separate incident

A military police investigation ruled on Tuesday, meanwhile, that Canadian soldiers involved in the shooting deaths of two Afghan children near Kandahar in July did nothing wrong and followed proper procedures.

The investigation found the soldiers had followed proper procedures before firing a single round from a 25-mm cannon into a speeding vehicle that came within 10 metres of their convoy.

Four-year-old Maraka and two-year-old Tor Jan were killed July 27 in the Panjwaii district southwest of Kandahar City.

Military officials said at the time that the soldiers involved flashed the lights on their vehicles, made hand gestures and issued audio warnings for the vehicle to pull over before they fired.

The coalition runs frequent public service announcements and advertising campaigns aimed at keeping locals informed about what to do when they see a military convoy.

Civilian casualties more commonly result from coalition air strikes.

On Aug. 22, up to 90 civilians, including 60 women and children, were killed in an air attack on a village compound in the Herat province, according to Afghan accounts.

Among the 577 civilians killed by U.S.-led Western forces or the Afghan National Army this year, more than two-thirds were killed by air strikes, said a UN report released on Tuesday. In the same period last year, pro-government forces were responsible for 477 civilian deaths.

Concerns over military operations in Afghanistan

Afghan president Hamid Karzai has repeatedly pleaded with western forces to take strides to prevent civilian casualties, deaths that undermine the national government and angers locals.

In June, a UN investigator criticized the Canadian military for a lack of accountability for civilian deaths in Afghanistan.

Philip Alston, the UN's special rapporteur on extrajudicial, summary or arbitrary executions, said in an interview with CBC News that senior Canadian military officials and other NATO officials had denied him access to details about civilian casualties.

Alston said in a May report that secrecy and a dearth of public information regarding the casualties were jeopardizing support for the mission.

NATO has described Alston’s report as exaggerated and inaccurate.

There are currently about 2,500 Canadian troops serving in the southern province of Kandahar.

With files from the Canadian Press