(CNN) -- The soldiers of Bravo Company 2-16 Infantry had been under fire all morning from rocket-propelled grenades and small arms on the first day of Operation Ilaaj in Baghdad.
Two Apache attack helicopters, code-named Crazyhorse 18 and 19, headed out to help the ground troops clear insurgents from an area of the New Baghdad district of the Iraqi capital.
Forty minutes later, nine people in the street were dead, including a photographer and his assistant for the news agency Reuters. Two Iraqi children were injured, while U.S. forces suffered no casualties.
The engagement on July 12, 2007, gained international attention because of the deaths of the Reuters journalists.
Now, aerial footage from one of the helicopters made public by the Web site WikiLeaks has led to new revelations about exactly what happened in the sweltering heat that morning.
WikiLeaks, which publishes anonymously submitted documents, video and other sensitive materials, posted the aerial footage Monday.
The video footage showed that one of two photojournalists killed was being rescued when the gunship's crew fired on the van to which he was being carried. Saying the footage was still classified, Wikileaks contended it "clearly shows the unprovoked slaying of a wounded Reuters employee and his rescuers."
On Tuesday, the Pentagon made public a partially redacted report on the incident that concluded the Apache attackers had no way of knowing the journalists were among suspected insurgents on the street.
"It must be noted that details which are readily apparent when viewed on a large video monitor are not necessarily apparent to the Apache pilots during a live-fire engagement," the report said, adding that the pilots viewed the scene on a much smaller screen while trying to fly safely and look for enemy insurgents.
From that perspective, the journalists' cameras looked like weapons carried by the suspected insurgents, including rocket-propelled grenades and assault rifles, according to the report. In addition, the journalists lacked any distinctive clothing or markings to distinguish themselves from the combatants, the report said.
In a statement posted on the Reuters Web site Tuesday, the agency's editor-in-chief, David Schlesinger, called the footage "difficult and disturbing to watch, but also important to watch."
"I will continue to campaign for better training for the military -- to help as much as possible to teach the difference in form between a camera and an RPG or between a tripod and a weapon," Schlesinger's statement said.
The two photojournalists were Saeed Chmagh and Namir Noor-Eldeen. In the video footage, both can be seen carrying photo equipment as they walked in the streets of New Baghdad on the morning of the incident.
From the limited view of an aerial camera mounted on a helicopter gunship, the scene appears relatively calm. The journalists walk in the middle of the road amid a group of men, seemingly unconcerned about potential imminent danger.
To the military, the group of "military-aged men" represented a threat that required engagement.
Retired Army Brig. Gen. Mark Kimmitt told CNN on Tuesday the incident occurred at the height of the insurgency on a morning when fighting had occurred for four hours.
According to the investigation report dated July 17, 2007, five days after the incident, two in the group of men carried cameras with long lenses while some others had weapons including rocket-propelled grenades and automatic rifles.
"The cameras could easily be mistaken for slung AK-47 or AKM rifles, especially since neither cameraman is wearing anything that identifies him as media or press," the report says.
In the Apaches, the aerial attackers notified each other of weapons being carried by the group in the street.
"That's a weapon," says one voice on the transcript of the video. A few seconds later, a voice in Crazyhorse 18 confirms: "Have individuals with weapons."
"Yup, he's got a weapon, too," says the next recorded voice a few seconds later.
The helicopters get ready to attack, with a request to engage, or shoot, "five to six individuals with AK-47" rifles.
"Roger that. Uh, we have no personnel east of our positions. So, uh, you are free to engage. Over," comes the reply.
However, the men on the street have moved toward a building that blocks them from the view of the aerial camera, prompting the following comments on the helicopters' transcript:
"I can't get 'em now because they're behind that building," one voice says. Seconds later, another says one of the men on the street has a rocket-propelled grenade.
Again, the building obscures the view from the helicopters. The frustration becomes evident in the voices on the transcript.
"Yeah, we had a guy shoot -- and now he's behind the building," one voice says, while another curses.
"Just [expletive], once you get on 'em, just open 'em up," says one voice.
Seconds later, that is exactly what happens.
"You're clear," a voice says, followed by another that says, "All right, firing."
Multiple voices ensue, with calls of "Let's shoot," "Light 'em all up," and "Come on, fire."
A few seconds later, a voice says: "All right, we just engaged all eight individuals." In the ensuing exchange of information, one voice says: "All right, hahaha, I hit 'em."
On the ground, the group had gathered on the side of the road with little visible awareness of what was about to happen.
They are instantly cut down by the strafing from the Apache gunship's 30 mm machine gun and enveloped in a cloud of smoke and dust.
Asked by CNN why the men in the street appeared unprepared for the attack, Kimmitt noted the helicopter could have been as far as 800 meters away and might have looked to be circling the general area rather than focusing on them.
"What you're looking at is a screen under high magnification," Kimmitt said. "So it's very clear that had they seen helicopters aiming at them, they probably would have taken some different action. But our technology is such that we can do this from quite a distance away."
One of the journalists, Noor-Eldeen, appears in the video footage to have been killed in the first round of strafing. It shows that Chmagh surviving the initial shooting, but apparently he died when the gunship opened fire on people attempting to get him to a van that arrived, apparently to collect the wounded.
"We have individuals going to the scene, looks like possibly, uh, picking up bodies and weapons," says a voice on the transcript a few minutes after the initial shooting.
Repeated requests to open fire get no response, and voice can be heard saying: "Come on, let us shoot."
The order to engage, or start shooting, comes shortly thereafter. About 90 seconds later, a voice says: "No more shooting."
In the following minutes, ground soldiers on the scene find two wounded Iraqi children at the scene. The investigation report describes one of the children as a young girl in the van, who suffered a stomach injury.
"This tragic incident was investigated at that time by the brigade involved, and the investigation found that the forces involved were not aware of the presence of the two reporters, and that all evidence available supported the conclusion by those forces that they were engaging armed insurgents, and not civilians," Maj. Shawn Turner, a U.S. military spokesman, told CNN in a written statement Monday.
Turner rejected any insinuation that the U.S. Army tried to cover up the manner in which the journalists were killed, saying: "We regret the loss of innocent life, but this incident was promptly investigated, and there was never any attempt to cover up any aspects of this engagement."
The U.S. command in Iraq said the video was "presumably associated" with the raid that led to the two journalists' deaths, but said it was still working to verify the authenticity of the footage.
A total of 139 journalists, nearly 120 of them Iraqis, have been killed during the 7-year-old war, according to the New York-based Committee To Protect Journalists. At least 16 of those were killed by U.S. fire, and the committee said the video released Monday "raises questions about the actions of U.S. military forces and the thoroughness and transparency of the investigation that followed."
"This footage is deeply disturbing and reminds us of what journalists in war zones undergo to bring us the news," Joel Simon, the group's executive director, said in a written statement. "The video also confirms our long-held view that a thorough and transparent investigation into this incident is urgently needed."
Reuters' Schlesinger said the video footage, while difficult to watch, showed the extreme difficulties and threats that face journalists in conflict zones.
"There is no better evidence of the dangers each and every journalist in a war zone faces at any time," Schlesinger's statement said.
Along with his promised push for journalists' safety, Schlesinger said he also would "continue to press for thorough and objective investigations," and that he and Thomson Reuters Chief Executive Officer Tom Glocer would seek a meeting with Pentagon officials to "press the need to learn lessons from this tragedy."
"What matters in the end is not how we as colleagues and friends feel; what matters is the wider public debate that our stories and this video provoke," his statement said.
CNN's Adam Levine and Barbara Starr contributed to this report.