Pte. Robert Costall, 22, was killed by friendly fire from U.S. special forces, a U.S. army report suggests. ((DND/Canadian Press))

A U.S. army report made public Monday said it was friendly fire that killed a Canadian soldier and an American soldier in Afghanistan in March 2006.

The report was released to the Associated Press through a Freedom of Information Act request.

It said Pte. Robert Costall, a 22-year-old Edmonton-based soldier, was shot from behind by U.S. special forces. Theywere firing a machine gun from an armyoutpost during a nighttime battle with Taliban insurgents in the Helmand province.

Sgt. John Thomas Stone of the Vermont National Guard was shot once in the back and once in the head by machine-gun rounds as he crouched behind a wall during the same battle, the report said.

Other coalition soldiers were injured in the battle.

Costall's wounded comrades had raised the possibility of friendly fire being to blame. The U.S. and Canadian army have been probing the incident.

The report obtained by the Associated Press is based on a collection of witness statements assembled by U.S. investigators.

Special forces soldiers gave their accounts of the March 29 battle, but the report does not include statements from Canadians at the scene, or the soldier who was manning the M240 machine-gun that allegedly killed Costall and Stone.

One witness,asergeant,recalled how aspecial forces security unit inone corner began shootingtoward the perimeter of the battle.

"I immediately realized the[special forces]was shooting at the Canadian position,"the sergeant, identified only as Witness 1, said in the report.

He said he whistled to signal the special forces soldiers to stop firing.

"The [special forces] security then turned his weapon 100 to 140 degrees from its original position and began firing in the direction of the American ETT compound," the witness said, referring to the location where Stone was hit.

The report does not indicate if anyone was disciplined.

Expected an attack

Costall's platoon — the 1st Battalion Princess Patricia's Canadian Light Infantry — was rushed in to the outpost on March 29 to reinforce theAmericans stationed there.

Soldiers expected the base to be attacked in retaliation foran earlycoalition attack on Taliban fighters in the area.

Costall, a machine-gunner, was born in Thunder Bay, Ont., and grew up in Gibsons, B.C.

In February 2006, he celebrated his son's first birthday and then shipped off to Afghanistan the next day.

Sixty-one Canadians have been killed in Afghanistan since the mission began in 2002.

With files from the Associated Press and Canadian Press