A representative of the Iraqi media read out a statement on Friday at the start of the news conference, condemning Thursday's killing of the two journalists from the Dubai-based al-Arabiya television channel, as Powell and Iraq's US occupying adminstrator Paul Bremer looked on.
One journalist stood up as soon as Powell walked into the room at the Baghdad convention centre and read a statement saying that after one year of "US occupation," Americans cannot provide security in Iraq.
"We demand an open investigation in front of the mass media," the Arab journalist said. "We also demand that security be guaranteed to journalists" working in Iraq, he said.
Seconds later, more than 20 journalists walked out of the room.
The death brought to five the number of journalists killed in Iraq in less than 24 hours.
Six journalists have been killed
in Iraq by US forces since 1 May
The US military said it had no information on the shootings of the correspondents late on Thursday. But it reported the shooting death of an Iraqi at a checkpoint, and the time and place of that death matched details reported by al-Arabiya about the incident involving its Iraqi staffers.
Powell started the conference after the protest saying he regretted the deaths of two journalists shot by US troops.
"I also regret the loss of life, the two journalists that they commemorated here by their action, I regret any loss of life," Powell told the remaining reporters.
In total, six journalists have been killed at the hands of US occupying soldiers in Iraq since George Bush declared an end to major combat on 1 May 2003.
Correspondent Ali al-Khatib died on Friday in hospital in Baghdad. The station's cameraman Ali Abd al-Aziz died on Thursday from a gunshot wound to the head after US troops opened fire on their car at a checkpoint.
News correspondent al-Khatib and
cameraman Abd al-Aziz both died
Al-Arabiya on Thursday called the shootings a "horrid crime" and demanded an investigation. A member of the Iraqi Governing Council on Friday strongly condemned the US forces, saying the shooting was a "clear aggression".
"This is an absolutely clear aggression by the occupation forces against the media," Muhsin Abd al-Hamid told al-Arabiya.
"We've told them before not to behave like this. They have the right to defend themselves but not to kill people like this in the street at random," he added.
The driver of the car carrying al-Arabiya journalists said US troops fired at random after they sped away from the checkpoint when another car approached at speed.
A US military spokesman said troops had shot dead an Iraqi after his car ran through a checkpoint and hit a Humvee. He said the Iraqi was the only person in the car and had no information on whether any journalists were killed or wounded.
"It's a tragic event and we demand an immediate investigation and accountability concerning those who are responsible for this," an al-Arabiya spokesman told Reuters on Friday after news of the second death.
"They were shot when they were going away from the checkpoint, not approaching it, so they were shot from the back. This is what eyewitnesses from the bureau are saying," he added.