(CNN) -- Guantanamo Bay detainee Omar Khadr pleaded guilty to charges against him Monday, the Pentagon said, in the first military commission trial there since Barack Obama became president.
Khadr, 24, was accused of throwing a grenade during a 2002 firefight in Afghanistan that resulted in the death of Army Sgt. 1st Class Christopher Speer, a Special Forces medic.
He also admitted that he "converted landmines to Improvised Explosive Devices and assisted in the planting of 10 IEDs with the intent of killing American forces" in the months before killing Speer, the Pentagon said.