Specialist Nathan Lynn was charged with voluntary manslaughter for allegedly shooting an unarmed man on February 15.
Lynn and a second soldier, Sergeant Milton Ortiz Jr, were charged with obstructing justice for allegedly conspiring with another soldier who reportedly put an AK-47 near the body in an attempt to make it look as though the dead man was a fighter.
Ortiz was also charged with assault and communicating a threat in a separate incident on March 8. He allegedly put an unloaded weapon to the head of an Iraqi man and threatened to send him to prison.
The soldier who allegedly placed the weapon near the body was redeployed and left the army before criminal proceedings began.
Both soldiers - from the 1st Battalion, 109th Infantry (Mechanised) of the Pennsylvania National Guard - are being held in Baghdad while they await hearings which will determine if there is enough evidence to hold to a court martial.
A US soldier convicted of killing an Iraqi cow herder has been released from a military prison almost a year early, his lawyer said.
Army Specialist Edward Richmond Jr was convicted of voluntary manslaughter in August 2004 and sentenced to three years in jail.
Richmond was found guilty of shooting Muhamad Husain Kadir in the back of the head in the village of Taal Al Jal, which is about 65km southwest of Kirkuk.
Richmond was released on parole from an Oklahoma military prison on Friday.
"He told me this morning it feels good to be free," said his father, Edward Richmond Sr.
The soldier said that he shot Kadir because he thought he lunged at the soldier who was holding him and that he was not aware Kadir's hands were bound.