The two men are the first to be referred a court-martial in a prosecution that has lost some momentum, with charges dismissed against four men since it began last December.
Lt. Col. Jeffrey Chessani was one of four officers initially charged in the killings that sparked international anger. He is charged with dereliction of duty and failing to report accurately and investigate the incident.
The Marines also announced on Friday that Lance Cpl. Stephen Tatum would face a court-martial on involuntary manslaughter and other charges, dropping original charges of murder against him.
Lt. Gen. James Mattis, the commander of U.S. Marine Corps Forces Central Command, referred the charges against the two men after reviewing evidence presented in pretrial evidentiary hearings known as Article 32 proceedings.
"Lt. Gen. Mattis made his decision after consideration of information developed from investigations by Marine, Army and Naval Criminal Investigative Service investigators, as well as evidence produced during an Article 32 investigation hearing," the Marines announced in a statement.
The Marines relieved Chessani of his command in April 2006 after a Time magazine story detailed the November 19, 2005, killings that followed a bomb attack that killed a popular young Marine.
Chessani passed on a letter from the Haditha town council asking for a probe of the killings but did not begin an investigation.
Testimony in military court has shown that Marines in the unit shot dead five unarmed men after ordering them out of a car, then killed other 19 people, including women and children in two nearby houses.
Tatum was one of the Marines who "cleared" the homes in the incident, according to testimony. Lance Cpl. Humberto Mendoza said in August that Tatum told him to shoot a group of Iraqi women and children he found on a bed in a closed room.
The Oklahoma-native Tatum was serving his second tour of duty when the Haditha killings occurred. During his initial tour, he saw heavy fighting at the battle of Falluja in 2004.
"...LCpl Tatum did not commit any crime, and we will take the fight to the courtroom," his lawyers Kyle Sampson and Jack Zimmermann said in a statement.
"We will vigorously challenge the government's case, and nothing will be left undone in defense of this fine young Marine."
Mattis has not yet announced a decision on whether to go ahead with a court-martial against Staff Sgt. Frank Wuterich, the unit leader who has admitted to shooting some of the Iraqi civilians. The Marine said he acted in a response to attacks.
An evidentiary hearing against one other Marine is scheduled to take place in the coming weeks.
© 2007 Reuters