BAGHDAD, Iraq (CNN) -- It was last Sunday in western Baghdad. Helicopters circled overhead while armed guards, privately hired by the U.S. government, were conducting an ordinary mission to protect U.S. State Department employees.

Hasan Jaber Salman, wounded in the incident, says of Blackwater contractors: "No one fired on them."

But within minutes there was an explosion, a hail of gunfire, and bodies in the streets.

The Iraqi Interior Ministry says at least 10 Iraqis were killed and 10 wounded. Another government spokesman, Ali al-Dabbagh, told CNN that at least 20 people died, with 35 wounded.

So what happened on that day on a square in the Mansour district of Baghdad?

It depends on whom you ask.

Blackwater USA, the private security firm at the center of the controversy, says its employees simply defended themselves against armed attackers.

Two men hospitalized with gunshot wounds disagree. They say the guards fired on people for no reason.

Hasan Jaber Salman lies in Yarmouk Hospital, bandages covering gunshot wounds in his back.

Salman says he is a lawyer who was headed from a courthouse to the Ministry of Justice when he found his route blocked by four armored Blackwater SUVs.

The roadblock soon caused a traffic snarl, so armed Blackwater guards began waving at the drivers, telling them to turn around and leave the area.

"So we turned back, and as we turned back they opened fire at all cars from behind," Salman said. "All my injuries, the bullets are in my back.

"Within two minutes the security force arrived in planes -- part of the security company Blackwater. They started firing randomly at all citizens."

Blackwater, in a statement issued after the incident, denied that gunfire came from aircraft. "The helicopters providing aerial support never fired weapons," it said.

The firm also said its employees "acted lawfully and appropriately in response to a hostile attack."

But Salman claims the attack was unprovoked.

"No one fired at them, they were not attacked by gunmen, they were not targeted by an explosion," he said. Watch the survivors describe what happened »

The firing continued until Salman's car crashed into a police checkpoint and flipped over, he said, adding that eight bullets struck his car and four struck him.

"My left shoulder is broken ... and my arm is broken. I had a surgery. ... They opened up my stomach," he said. "I swear to God no one did anything to them at all."

The lawyer said he intends to sue Blackwater, which he already did in 2005 after his son was involved in a similar incident outside al-Muthana Air Base near Baghdad's international airport. That lawsuit has not yet been resolved, he said.

Laborer Abul-Raheem Amir said he was on his way to a job when the minibus he was in got caught in a traffic jam caused by an explosion.

"A security company called Blackwater, they got out and kept on firing randomly at people, starting with the people walking or working the street -- even the traffic policeman, even the people who work in the area," Amir said.

"People at first thought we were safe in the minibus, but when they realized they were not, they started getting out and went to other places to save themselves," he recounted. "Unfortunately that did not work. As they got out, people were shot and killed."

He said he tried to make a run for it after the driver and two women next to him on the minibus were shot.

"I ran about 50 meters [about 55 yards] and then was shot, the first bullet. Still I kept running, but the second bullet dropped me to the ground. ... It broke my bones, and the third one made me start crawling."

Some people helped get him off the street and away from the carnage. The shooting lasted for about a half-hour, and there were some 30 bodies in the street, he said.

"I remember people strewn on the streets, children, elderly, young men, elderly women. ... The street turned into the street of the dead, a graveyard," he said.

"There was nothing I could do. Every man was for himself."

Amir wonders what the Blackwater employees were thinking.

"Is this some kind of a show of force for them to flex their muscles?" he said. "Are they doing this to us, the victims, so they can advertise and promote their abilities through the Western media? ... Is their mission to protect one person by killing 10 unarmed people? And if they are protecting two people, then they shoot 100 unarmed people. ... Is this Vietnam? ...

"Enough, enough," he said. "Enough of all that's happening. God's fury is coming. Enough of this. Enough." E-mail to a friend

CNN's Aneesh Raman and Jomana Karadsheh contributed to this report.

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