WASHINGTON -- Pennsylvania's Rep. John P. Murtha was sued for defamation yesterday by a Marine Corps sergeant under investigation in connection with the deaths of Iraqi civilians in Haditha.

Lawyers for Sgt. Frank D. Wuterich, 26, argue in a federal lawsuit that the Johnstown Democrat falsely accused Sgt. Wuterich of "cold-blooded murder and war crimes." But they acknowledged during a news conference that Mr. Murtha identified Sgt. Wuterich's squad, but not Sgt. Wuterich by name, when speaking with reporters.

"His real problem is not his lawsuit against me, it's defending himself in court," Mr. Murtha told reporters yesterday while campaigning in his hometown.

In a statement earlier yesterday, the 16-term congressman said he does not blame Sgt. Wuterich for "lashing out." Mr. Murtha added, "When I spoke up about Haditha, my intention was to draw attention to the horrendous pressure put on our troops in Iraq and to the cover-up of the incident."

The suit contends that Pentagon officials "who have briefed or leaked information to Mr. Murtha deliberately provided him with inaccurate and false information," and that Mr. Murtha subsequently "has made repeated statements ... that are defamatory" to Sgt. Wuterich and his fellow Marines.

The suit accuses Mr. Murtha of spreading "false and malicious lies" about Sgt. Wuterich and his squad that were "intended to serve his own private purpose and interests." It says many of Mr. Murtha's comments were made outside his "scope of employment as a congressman." Mr. Murtha, a former Marine and decorated Vietnam War veteran, has been a leading proponent of withdrawing U.S. forces from Iraq.

The claim for libel and invasion of privacy seeks damages to be determined, but not less than $75,000.

The suit details Sgt. Wuterich's account of what happened on Nov. 19, 2005, in Haditha.

Sgt. Wuterich says several civilians were killed when his squad pursued insurgents, firing at them from inside a house after a roadside bomb killed one Marine. He describes a house-to-house hunt that went wrong in the midst of a confusing battlefield, but has denied through his lawyers any vengeful massacre.

Sgt. Wuterich and other Marines from his 3rd Battalion, 1st Marine Regiment, are under investigation by the Naval Criminal Investigation Service.