Canadian troops in Kandahar city accidentally killed an Afghan civilian who refused to stop when approaching a security cordon, NATO said Tuesday.

There are reports that the man who was killed was distinguished religious figure in Kandahar.

"What is known for sure is that he had at, one point at least, been a member of a religious consultative body that was advising the Afghanistan government on how to deal with the insurgency and the Taliban in this region," CTV's Murray Oliver reported from Kandahar.

NATO said the motorcyclist was travelling at high speed when he approached a security cordon near where Afghan President Hamid Karzai was meeting with senior Canadian officials, including Canadian ambassador David Sproule.

Speculation is that the man was well known enough by Afghan officials that he was passed through, Oliver said.

But it was when he reached the inner security cordon that he was warned to keep away.

Despite verbal warnings, the motorcyclist refused to stop.

"A Canadian soldier challenged him to stop, he apparently didn't understand the order -- at least this is the way the story goes. The Canadian soldier, according to the Canadian army, filed a single warning shot into the ground, that shot ricocheted and then hit the man on the motorcycle," Oliver said.

Afghan National Police officers were on the scene to immediately transport the casualty to the local hospital, where he was pronounced dead on arrival.

A statement from NATO's International Security Assistance Force says the loss of life was regrettable and it was unclear why the motorcyclist refused to heed the warning.

"It is not known why the motorcyclist failed to stop when clear signals were given, and a full and thorough investigation has commenced," says the statement from the ISAF.

The Canadian military has said it believes the soldier who fired the shot followed all the reasonable rules of engagement, Oliver reported.

NATO spokesman Mark Laity told The Associated Press on Wednesday that troops take extra measures to minimize the risk to civilians.

"When something does happen -- and it does I'm afraid -- we are not only upset, we do not only apologize, we investigate to see what steps we can take to minimize the risk in the future,'' he said.

The death came as Karzai met Western diplomats to discuss how to prevent civilian casualties in military operations.

The presence of Karzai put the troops on heightened alert, Oliver said.

"Kandahar was of course once the centre of Taliban resistance and remains a Taliban hotbed ...so for sure there was a lot of tension at this gathering," he said.

Afghan anger has been fuelled by a series of civilian deaths during NATO fighting with the Taliban and in the aftermath of suicide bombings.

"We are rightly angered by it and worried by it,'' Karzai said Tuesday.

"NATO is also worried by it, and is working with us to reduce such casualties.''

NATO on Tuesday said four militants and a teenage girl were killed during an early morning raid by Afghan and U.S.-led coalition forces in the eastern province of Khost.

But a police official on Wednesday disputed that account, saying only civilians in the home were targeted. The official asked not to be identified for fear of retribution.

Forty-four Canadian soldiers and one diplomat have been killed since the Afghan mission began in 2002, the majority of those casualties this year.