Washington: Heavier guns and sturdier trucks would not have saved a team of  Blackwater USA guards brutally killed in March 2004 after being lured by corrupt Iraqi forces into a well-planned ambush, the embattled private security contractor contends in a report to Congress.

This conclusion sharply contradicts the findings of a congressional investigation led by House Democrats and a wrongful death lawsuit filed by the families of the four slain guards.

Blackwater is cast in both as an incompetent, penny-pinching outfit that sent an undermanned and poorly equipped detail through Fallujah, a known insurgent stronghold 40 miles west of Baghdad.

In the 10-page report, obtained by AP and delivered Tuesday to lawmakers, Blackwater says Democrats and the lawyer for the families have teamed up against the company for political gain.

While calling the deaths ''a tragic event,'' Blackwater says the incident was unavoidable and the guards -- former Navy SEALs and Army Rangers -- understood the risks of their mission and could have refused to go.

''Stronger weapons, armored vehicles, ammunition or maps would not have shielded these brave military veterans from the certain death that awaited them on that morning,'' Blackwater says. ''Even if Blackwater had placed six men on the mission, the result would likely have been the same.''

Members of the Iraqi Civil Defense Corps, swayed by sectarian influences, ''intentionally betrayed'' the Blackwater guards, the report says -- a deception no amount of equipment, training or skill could overcome.

Blackwater does not say the civil defense forces killed the guards, however. Unidentified ''terrorists'' were responsible for the murders, it says.

''It was ICDC betrayal and enemy ambush -- not contractor incompetence -- that led to the deaths of four Blackwater personnel on March 31, 2004,'' the company says.

In a Sept. 27 report on the Fallujah incident, the Democratic staff of the House Oversight and Government Reform Committee agreed the guards were ambushed by insurgents but said there was no evidence the civil defense corps participated.

Written in response to the Democratic staff's findings, Blackwater's Fallujah report is the latest rumble in the volatile debate over the company's performance and its future as the protector of US diplomats in Iraq.