A court-martial began Monday of a National Guardsman accused of passing military information to undercover agents he thought were Al Qaeda (search) members.

Spc. Ryan Anderson (search), 27, could get life in prison without parole if convicted.

Anderson, a Muslim convert, pleaded innocent Aug. 9 to five counts of trying to provide the Al Qaeda terrorist network with information about U.S. troop strength and tactics, and methods for killing American soldiers.

Capt. Jay Stephenson, a spokesman for the military prosecutors, said the charges against Anderson amount to attempted treason.

"We're at war now," Stephenson said Monday. "This is a big thing. This is a very serious and grievous offense."

Undercover investigators met with Anderson at a parking lot near the Space Needle in Seattle, where an hour-long discussion was secretly recorded on Feb. 9, just days before Anderson was to leave for Iraq with his unit, the Washington National Guard's 81st Armored Brigade.

On the video, Anderson offers sketches and information about weaknesses in the M1A1 Abrams (search), the Army's primary battle tank, authorities said. He was arrested at Fort Lewis three days after the meeting.

Anderson's attorney, Maj. Joseph Morse, has refused to comment.