We are going to talk to not only the witnesses who saw it, but also the chain of command

Maurice Baril, Canadian team leader

The US pilot reportedly thought he was under attack.

The head of the Canadian mission, former General Maurice Baril, said it was seeking a "very clear picture" of what had happened.

"We are going to talk to not only the witnesses who saw it, but also the chain of command, those who designed the training, authorised the training," he said on arrival.

His mission would check if the training had taken place under "the rules and regulations and the good tradition of the Canadians", he added.

Canada has an 800-strong contingent serving in Afghanistan as part of US-led coalition forces in the war against terror.

Prime Minister Jean Chretien led a mourning ceremony for the four dead soldiers on Sunday.

The losses have caused widespread anger in Canada with calls for the soldiers to be withdrawn.

The Canadian team is due to submit an interim report by 13 May and make final recommendations by 21 June, Reuters news agency reports.