Rep. John Murtha who — unlike President George W. Bush — served his country in war says the deaths of as many as two dozen Iraqi civilians and an ensuing cover-up threaten to do more harm to U.S. efforts in Iraq than even the Abu Ghraib prison scandal.

“This is the kind of war you have to win the hearts and minds of the people,” Murtha, D-Pa., said Sunday. “And we’re set back every time something like this happens. This is worse than Abu Ghraib.”

Murtha compared the shootings last November at Haditha, a city in the Anbar province of western Iraq, with the revelations that U.S. military personnel had abused and humiliated Iraqi detainees at Abu Ghraib, a U.S.-run prison outside of Baghdad. The prison scandal severely damaged the U.S. effort to win over the Arab world by fostering a democratic government in Iraq.

A bomb rocked a military convoy in Haditha on Nov. 19, killing a Marine. Marines then shot and killed unarmed civilians in a taxi at the scene and went into two homes and shot other people, according to Murtha.

Murtha said high-level reports he received indicated that no one fired upon the Marines and there was no military action against the U.S. forces after the initial explosion. Yet the deaths were not seriously investigated until March because an early probe was stifled within days of the incident, he said.

“Who covered it up, why did they cover it up, why did they wait so long?” Murtha said on This Week on ABC. “We don’t know how far it goes. It goes right up the chain of command.”

Lt. Col. Scott Fazekas, a Marine Corps spokesman, told The Associated Press the investigation was ongoing and he would have no comment.

Murtha, a decorated former Marine who has criticized the Bush administration’s conduct of the war, repeated his view that the war cannot be won militarily and needs political solutions, which he said were damaged by such incidents involving the U.S.

The incident at Haditha has sparked two investigations _ one into the deadly encounter itself and another into whether it was the subject of a cover-up.

The second, noncriminal investigation is examining whether Marines sought to cover up what happened that day and, in doing so, lied about having killed civilians without justification. The Marine Corps had initially attributed 15 civilian deaths to the car bombing and a firefight with insurgents, eight of whom the Marines reported had been killed.

A defense official, who spoke on condition of anonymity because he was not authorized to speak publicly, told The Associated Press on Friday that evidence gathered so far strongly indicated that the Haditha killings were unjustified.

Early this year, a videotape of the aftermath of the incident, showing the bodies of women and children, was obtained by Time magazine and Arab television stations. The military then undertook another investigation.

Sen. John Warner, R-Va., chairman of the Senate Armed Services Committee, said he would hold hearings on the incident but cautioned against reaching conclusions until the military completed its investigation.

“There is this serious question, however, of what happened and when it happened and what was the immediate reaction of the senior officers in the Marine Corps when they began to gain knowledge of it,” Warner said on ABC.

The Naval Criminal Investigative Service investigation into the shootings is ongoing. Whether violations of the Uniform Code of Military Justice, including murder, would be pursued would be determined by a senior Marine commander in Iraq.

The NCIS also is conducting a criminal investigation into another incident, the April 26 death of an Iraqi civilian involving Marines in Hamandiyah, west of Baghdad.