Canadian soldiers were shooting into the air during a live-fire training exercise in Afghanistan at least 10 minutes before a U.S. F-16 mistakenly dropped a bomb on their position, killing four Canadian soldiers and injuring eight, according to testimony by surviving soldiers.

The transcripts were not included in final reports issued by U.S. and Canadian investigative boards, which found the U.S. pilots at fault in the April incident.

Two Canadian soldiers told investigators that they were shooting at targets above them during the nighttime exercise and that the tracer bullets went toward the sky.

"There would have been rounds, like a short burst going into the air to begin with," according to testimony from Sgt. Lorne Ford, who was injured in the attack.

Cpl. Rene Paquette testified: "I fired two or three bursts at a target. . . . It was almost directly up."

The two U.S. Air Force pilots, the first service members to face criminal charges in a friendly fire incident during the war in Afghanistan, have argued that they dropped the bomb in self-defense in response to what they thought was hostile fire from the ground.

The testimony, which was included in 16,000 pages of documents used to compile the final reports, might be considered during the proceedings against the two U.S. pilots and could bolster their case. The pilots were charged in September with involuntary manslaughter and assault for dropping the bomb. A preliminary hearing is scheduled for Jan. 13 at Barksdale Air Force Base in Louisiana.

Maj. Harry Schmidt was charged with disregarding the Pentagon's rules of engagement governing the conflict in Afghanistan. Maj. William Umbach was charged with negligently failing to exercise appropriate flight command and failing to order Schmidt to hold his fire. The pilots could each face 64 years in prison if convicted.

Canadian officials acknowledged today that the Canadian soldiers had testified they were shooting toward the sky and that their testimony was in the documents used in compiling the final report. "We spoke to people and they did talk about the incidents," said Navy Lt. Diane Grover, a spokeswoman for Canada's National Defense Department. "Everybody had access to the same information. It is just our board decided not to address the issues like that. We fully stand behind what we produced."

A spokeswoman for the U.S. Air Force declined to comment. "The Article 32 [preliminary] hearing is the proper forum. The uniform code of military justice is fair and sound, and it is an open hearing," Capt. Denise Kerr said.