WASHINGTON (CNN) -- A decorated Marine colonel turned anti-war congressman has said that Marines killed at least 30 innocent Iraqi civilians "in cold blood" in Haditha in November, suggesting the attack is twice as bad as originally reported.

Rep. John Murtha, D-Pennsylvania, told reporters Wednesday that he got his information from U.S. Commanders, who said the investigation will show that the Marines deliberately killed the civilians.

The U.S. Marine Corps has declined to comment on the report, which initially stated that 15 were killed.

"There was no firefight. There was no IED that killed these innocent people. Our troops overreacted because of the pressure on them, and they killed innocent civilians in cold blood," Murtha said. (Watch Murtha level accusations against the Marines -- 1:58)

Murtha, who was decorated for his service in Vietnam, said the death toll may be more than twice as high as originally reported.

"They actually went into the houses and killed women and children," the congressman said.

Citing an ongoing investigation, the Marine Corps said, "Any comment at this time would be inappropriate and could undermine the investigatory and possible legal process."

The Iraqi civilians were killed while troops from the 3rd Battalion, 1st Marines were looking for insurgents who planted a roadside bomb that killed a member of their unit.

At first, the Marines said the civilians were killed by a roadside bomb. Later, they suggested the victims may have been caught in a firefight.

An Iraqi human rights group, Hammurabi Human Rights Association, caught the scene on video, which was obtained by Time magazine. A criminal investigation ensued.

Time Warner is the parent company of Time magazine and CNN.

Last month, the battalion commander and two company commanders were relieved of their commands and reassigned to staff jobs at Camp Pendleton in California.

Sources close to the investigation said it is too soon to say whether anyone will face criminal charges, but key aspects of the original Marine account have not checked out.

Murtha supported the invasion of Iraq in 2003, but last November, he distanced himself from the Bush administration and called for the withdrawal of U.S. Troops because of what he called "a flawed policy wrapped in illusion."

Well, of course; that's what soldiers are trained for, to kill! :S

Also it's hard for them to differentiate who's the good guy from the bad; potentially they are all enemies. Isn't preemption about killing before you get killed? Iraqis, Iranian, Middle-East dudes, it's all the same; are all part of the Axis of Evil, all enemy of the West!

Well spoken Hugo, I fully agree with you, and without being disrespectfull all the fuss when one of our soldiers (UK) or one of yours gets killed, yes it is bad but that is the life they wanted, that is what they are trained and paid for, so......???

I think Hugo was being sarcastic...

As I... I think if it had been three or four, it might have been a mistake. But 30?

This may sound very incosiderate but its the truth iraq doesnt have a milatary uniform they just were anything so how would a soldier know the difference

Hey! All of those kills still count. Some will argue that it takes two women or four children to be considered one kill. I disagree. A kill is a kill. Those are all quality and full points.

So yes, those marines got 30 points for the day and not 20 or 15 as some might say.

^^ Then don't kill someone. If you don't know the difference, give them the benefit of the doubt unless they're shooting at you. Geez, we're getting so paranoid...