WASHINGTON — Private security guards who worked for Blackwater repeatedly shot wildly into the streets of Baghdad without regard for civilians long before they were involved in a 2007 shooting episode that left at least 14 Iraqis dead, federal prosecutors charge in a new court document.

While traveling through Baghdad in heavily armored vehicles, at least one of the guards, under contract with the State Department to provide security for United States Embassy personnel, fired an automatic weapon “without aiming” while another deliberately fired into the streets to “instigate gun battles in a manner that was inconsistent with the use of force and escalation of force policies that governed all Blackwater personnel in Iraq,” the federal prosecutors stated.

The new accusations were included in a document filed by prosecutors last week in the criminal case against five former Blackwater guards who have been charged with manslaughter in federal court in Washington in connection with the shootings in Nisour Square, in Baghdad, on Sept. 16, 2007.

The guards have pleaded not guilty and have argued that they did not fire their weapons with criminal intent in the Nisour Square case.

The prosecutors are trying to prove that the shootings were part of a larger pattern of reckless behavior.

“These prior bad acts are relevant to establish that the defendants specifically intended to kill or seriously injure the Iraqi civilians that they fired upon at Nisour Square,” the court document says.

Part of the evidence relates to the states of mind of the Blackwater guards, and whether statements they allegedly made about killing Iraqis were factors in the shootings. The document says, for example, that one of the guards, Nicholas Slatten, told people that “he wanted to kill as many Iraqis as he could as payback for 9/11 and he repeatedly boasted about the number of Iraqis he had shot.”

The new allegations also seem to raise questions about whether there was adequate oversight of the security details by either Blackwater or the State Department.

Defense lawyers have not formally responded to the government’s latest document, and a defense lawyer for one of the guards reached on Sunday declined to comment. Previously, the defense stated that the government’s evidence was weak and that its case was without merit. The trial is set to begin in February.

The guards were indicted by a federal grand jury last December after a criminal investigation by the F.B.I. in Iraq and were arraigned in federal court in Washington in January. The case involves by far the bloodiest episode in Iraq linked to private security guards protecting American diplomats, and it has transformed the debate in both Washington and Baghdad over the proper role of private contractors in a war zone.

The Blackwater guards, assigned to a four-vehicle convoy known as Raven 23, drove into a traffic circle at Nisour Square in downtown Baghdad around noon that day and opened fire with a sniper rifle, machine guns and grenade launchers.

After the episode, Blackwater officials said that the guards had been responding to fire from insurgents, but prosecutors charge that they fired on unarmed civilians, including many who were shot in their cars while they were trying to flee.

The government points to specific prior incidents to make the case that the Nisour Square shootings were not isolated. In May 2007, one guard, Evan Liberty, fired his automatic weapon without aiming from the turret of a Blackwater vehicle near Amanat City Hall in Baghdad, according to the document.

That September, it states, Mr. Liberty was driving a vehicle near the same city hall and fired an automatic weapon without aiming and while still trying to drive. That second incident occurred just one week before the Nisour Square shootings.

Mr. Liberty and two other guards, Paul Slough and Mr. Slatten, were also said to have routinely thrown frozen water bottles, frozen oranges and other items at unarmed civilians and vehicles as they drove through Baghdad, “in an attempt to break automobile windows, injure and harass people, and for sport,” the court document states.

The two other guards named in the case are Dustin L. Heard and Donald W. Ball.

The document does not specify the source or sources of information for the new accusations. But in prosecuting the men, federal lawyers appear to be relying heavily on testimony from a sixth guard, Jeremy P. Ridgeway, who has pleaded guilty and is cooperating with the government.

Blackwater, which has changed its name to Xe Services, has not been charged in the case, but the shooting aftermath has hurt the company’s business deeply. This year, Xe (pronounced “zee”) lost its contract to provide diplomatic security for United States Embassy officials in Baghdad, and its longstanding, but more secret, ties to the Central Intelligence Agency have come under new scrutiny as well.

The shootings have caused a deep-seated political reaction in Iraq against private security contractors, leading the Iraqi government to demand successfully that the United States agree to make the contractors subject to Iraqi law.

Previously, the contractors had been granted immunity from Iraqi law, even while it was unclear which American laws governed their behavior.

The company also faces a civil lawsuit filed in the United States on behalf of the Iraqi victims that day.

This summer, Leon E. Panetta, the C.I.A. director, told Congress that he had found that during the Bush administration, the agency had once considered using Blackwater in a covert assassination program.

Officials have said that the plan was never implemented. But the company still has other contracts with the C.I.A., including one that calls for Xe’s personnel to handle and load bombs and rockets on Predator drones at secret bases in Pakistan and Afghanistan.