The lack of coordination among private contractors, coalition forces and Iraqi troops is one of the more startling revelations found in the more than 300,000 classified military documents recently made public by WikiLeaks. The reports shed new light on the Iraq war, including civilian deaths, detainee abuse and the involvement of Iran.

By JAMES GLANZ and ANDREW W. LEHREN

THE PRIVATE CONTRACTOR, wearing no uniform but fighting and dying in battle, reflects a critical change in the way America wages war. And recently released military documents reveal that the security contractors have allegedly committed so many abuses, including civilian deaths, that the Afghan government is working to ban many outside contractors entirely.

In the early days of the Iraq war, with all its Wild West anarchy, contractors were necessary, because there simply were not enough soldiers to do the job. Not only the military, but journalists and aid workers as well relied on contractors for protection. In 2004, the contractors’ presence became the symbol for Iraq’s descent into chaos, when four were killed in Falluja, their bodies left mangled and charred.

Even now, the military cannot do without them. There are more contractors than members of the military serving in the worsening war in Afghanistan. And the use of security contractors is expected to grow there as American forces shrink. The archive released by WikiLeaks, containing more than 300,000 classified documents, describes many episodes never before made public in such detail.

And it reveals how a failure to coordinate among contractors, coalition forces and Iraqi troops, as well as a failure to enforce rules of engagement that bind the military, endangering civilians as well as the contractors themselves. Contractors often shot with little discrimination - and few if any consequences - at unarmed Iraqi civilians, Iraqi security forces, American troops and even other contractors.

In one epi-sode reported in March 2005, a battle erupted involving three security firms. It is clear from the documents that the contractors appeared notably ineffective at keeping themselves and the people they were paid to protect from being killed.

And in stirring public outrage, they undermined much of what the coalition forces were sent to accomplish. Most of the documents match what is known of the few cases that have been made public, although even this cache is unlikely to be complete.

During the six years covered by the reports, at least 175 private security contractors were killed. Insurgents and other malefactors kidnapped at least 70 security contractors, many of whom were later killed. Aegis, a British firm, lost more than 30. The security contractors’ easily identifiable, surprisingly vulnerable vehicles were magnets for insurgents, militias and anyone else in search of a target.

In July 2007, one report said, two security contractors died when a truck operated by ArmorGroup, a British company, flew 49 meters through the air after a huge improvised explosive device detonated beneath it in northern Iraq. Death came suddenly, in all forms. There were suicide bombings, desert ambushes, aviation disasters and self-inflicted wounds, as when a Ugandan guard working for an American company shot and killed his South African supervisor and then himself in 2008 after being terminated, a report said.

The contractors also suffered horrific traffic accidents with multiple fatalities . And private security contractors repeatedly came under fire from Iraqi and coalition security forces, who often seemed unnerved by unmarked vehicles approaching at high speeds .

But whatever the reasons, the security companies are cited time after time for shootings that the documents label as unjustified. “AFTER THE IED STRIKE A WITNESS REPORTS THE BLACKWATER EMPLOYEES FIRED INDISCRIMINATELY ,” read one report from August 22, 2006, referring to the company, now known as Xe Services . Many of the companies apparently felt no sense of accountability.

Contractors with a Romanian company called Danubia Global killed three Iraqis in Falluja in 2006, another report said, then refused to answer questions on the episode, citing a company policy.

And still more recently, in July 2009, local contractors with the 77th Security Company drove into a neighborhood in the northern city of Erbil and began shooting at random, setting off a firefight with an off-duty police officer and wounding three women, another report said. “It is assessed that this drunken group of individuals were out having a good time ,” the incident report concluded.

In many other cases, contractors cited what they considered a justifiable “escalation of force” as an Iraqi vehicle moved toward them and did not respond to signals that the driver should stop. The Iraqis who were shot at, and who the documents show were nearly always civilians, not surprisingly saw things differently, and, to judge by the disgust apparent in some of the incident reports, American military units often had a similar perspective.

In December 2004, early in the war, shots were fired near Iraqi policemen in the port city of Umm Qasr by an American private security company named Custer Battles, according to one report. As the company’s convoy sped away, it shot out the tire of a civilian car that came close, then fired five shots into a crowded minibus. The shooting stopped only after the Iraqi police, port security and a British military unit finally caught up with the convoy.

Somehow no one had been hurt, and the contractors found a quick way to prevent disciplinary action. They handed out cash to Iraqi civilians, and left.