WASHINGTON A U.S. grand jury has opened an investigation into the shooting deaths of 17 Iraqi citizens in September by Blackwater private security employees guarding a U.S. Embassy convoy in Baghdad, ABC News reported on Monday.
ABC said on its Web site that several Blackwater guards were subpoenaed in the probe by the federal grand jury in Washington.
U.S. Justice Department spokesman Dean Boyd declined to comment.
Blackwater spokeswoman Anne Tyrrell said she could not confirm any probe. The company has said its guards acted lawfully after being shot at in the September 16 incident, when Blackwater guards opened fire as they conducted a convoy through Baghdad.
Blackwater has about 1,000 personnel to protect the U.S. mission and its diplomats from attack.
"We will cooperate with all investigations and we've always supported strong accountability," Tyrrell said. "If anyone was complicit in wrongdoing we want that person held accountable. Otherwise, we're withholding further comment until anything is final."
A grand jury determines whether a crime has been committed and there is enough evidence to bring a case to trial.
There are at least three investigations into the incident. The Iraqi government has called the killings deliberate. The U.S. military has said the guards acted without provocation. The New York Times reported that an FBI investigation found at least 14 of the 17 deaths were unjustified.
However, the issue of how U.S. contractors in Iraq could be pursued under U.S. law is murky. A State Department report last month urged more "legal clarity" and said it was unaware of any basis for holding non-U.S. defence department contractors accountable under U.S. law.
The ABC report said five Blackwater guards gave statements to State Department investigators in which they admitted firing their weapons. It said 12 others witnessed events but did not fire, and they gave conflicting statements on whether there were any hostile activities.
A reported focus of probe, a turret gunner named "Paul," said in his statement that he fired in response to small arms fire from a vehicle at the intersection and feared for his life, ABC has reported.
Also on Monday, two U.S. security guards and 31 other foreigners were among 43 people arrested by Iraqi security forces over a central Baghdad shooting in which a woman was wounded, an Iraqi government spokesman said.