The top Marine general said Thursday that he feared, based on two recent cases of alleged killings of civilians in Iraq, that some Marines could become "indifferent to the loss of a human life." His office announced that he was enroute to Iraq to reinforce the Corps' standards of behavior in combat.

"We do not employ force just for the sake of employing force. We use lethal force only when justified, proportional and, most importantly, lawful," Gen. Michael W. Hagee wrote in a statement issued by his office.

His statement and the announcement of his trip to Iraq came just hours after the Marine command in Iraq disclosed a criminal investigation into allegations that an unspecified number of Marines killed an Iraqi civilian west of Baghdad on April 26. Iraqis made the charge during a meeting with Marine officers on May 1.

"Many of our Marines have been involved in life or death combat or have witnessed the loss of their fellow Marines, and the effects of these events can be numbing," Hagee wrote. "There is the risk of becoming indifferent to the loss of a human life, as well as bringing dishonor upon ourselves."

A spokesman for Hagee, Col. David Lapan, said the general had scheduled the trip long ago but in light of the latest allegations he decided to use the visit as an opportunity to reinforce Marine Corps values and standards.

"To a Marine, honor is more than just honesty; it means having uncompromising personal integrity and being accountable for all actions," Hagee said in his statement. He urged all Marines to have the moral courage to "do the `right thing' in the face of danger or pressure from other Marines."

He referred to "recent serious allegations about actions of Marines in combat," but he did not specifically cite the two cases — one from last November and the other in April — of alleged killings of civilians.

In Wednesday's announcement of the latest criminal investigation, Marine officials said a preliminary investigation by Multinational Force-West, headed by Marine Maj. Gen. Richard C. Zilmer, had found enough information to recommend an investigation by the Naval Criminal Investigation Service.

The statement provided no details about the alleged killing, including either the gender or age of the victim. It said "several service members" from the 3rd Battalion, 5th Marine Regiment, which is based in the Fallujah area about 40 miles west of Baghdad, were suspected of involvement. They were "removed from operations" and sent back to the United States pending the results of the criminal investigation, it said.

A criminal investigation also is under way in connection with Marines from another battalion who are accused of killing at least 15 civilians, including women and children, last November in Haditha, 140 miles northwest of Baghdad.

The military initially described the Haditha encounter as an ambush during a joint U.S.-Iraqi patrol that involved a roadside bombing in which a Marine died, followed by a firefight. However, residents of the neighborhood maintained that only U.S. forces were shooting after the explosion.

Videotape aired by an Arab television station showed images purportedly taken in the aftermath of the encounter: a bloody bedroom floor, bullet holes in walls and bodies of women and children. An Iraqi human rights group called for an investigation of what it described as another deadly mistake that had harmed civilians.

The military began its administrative investigation to review whether the Marines involved had lied about what happened. A House committee will review the military's investigation next month.

On May 17, Rep. John Murtha, D-Pa., a decorated former Marine, said the toll in the Haditha attack was far worse than originally reported and that U.S. troops killed innocent women and children "in cold blood." He said that nearly twice as many people were killed than first reported, maintaining that U.S. forces are "overstretched and overstressed" by the war in Iraq.

Last August, the Marine Corps announced a criminal investigation into the death of the cousin of Iraq's ambassador to Washington, Samir al-Sumaidaie, who was shot and killed during a search of his home in Haditha on June 25.

No announcement has been made about the findings of the investigation.