A decorated Canadian officer was sentenced on Friday to a reduction in rank over a training incident in Afghanistan that killed a soldier and injured four others.

Major Christopher Lunney's rank was reduced to captain, the military announced in a statement.

He was in command during the February, 2010 training incident at a range northeast of Kandahar, when an explosive mine packed with steel balls raked a Canadian Forces platoon.

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The court martial heard that the reservists taking part in the exercise were ready for deployment to Afghanistan but it turned out they had received no advance training with the explosives that killed Corporal Josh Baker.

Capt. Lunney pleaded guilty to "negligent performance of a military duty."

Two of Capt. Lunney's subordinates also face charges in the incident. Their courts martial have not yet been convened.

Canada ended its combat mission in Afghanistan in 2011. The conflict claimed the lives of 157 Canadian soldiers over nine years. Nearly 1,000 military trainers, however, are still deployed in the country until 2014.