Veteran war correspondent Terry Lloyd, 50, who worked for British television company ITN, was killed in March 2003 in southern Iraq as he reported from the front line during the first few days of the U.S.-led invasion.

"He was fired on by American soldiers as a minibus carried wounded people away," Coroner Andrew Walker said at the conclusion of the inquest, which U.S. soldiers declined to attend.

"I have no doubt it was an unlawful act of fire on the minibus," Walker added.

He said he intended to write to the attorney general -- the government's top lawyer -- and the director of public prosecutions to try to bring those responsible for Lloyd's death before a British court.

Louis Charalambous, the Lloyd family's lawyer, said those responsible should be brought to trial for what he termed "a very serious war crime."

"It was a despicable, deliberate, vengeful act," he added.

He said the unlawful killing verdict had been "inescapable" and had come about because "U.S. forces appear to have allowed their soldiers to behave like trigger-happy cowboys."

U.S. Army Colonel Gary Keck, a Pentagon spokesman, said the death was a "tragic accident."

"We do not nor would we ever deliberately target a non-combatant, civilian or journalist," he said.

"We will continue to work with news organisations to do everything realistically possible to reduce the risk on an inherently dangerous battlefield but we must remember that there are inherent risks in covering a war."

CALLS FOR TRIAL

Charalambous said the Marines who fired on Lloyd, and their superiors, should stand trial for murder, a sentiment echoed by Lloyd's employers.

Joel Simon, executive director of the New York-based advocacy group the Committee to Protect Journalists, said: "The coroner's findings are alarming, and should trigger a comprehensive and public accounting by the U.S. military to determine whether legal or disciplinary action is warranted."

The ITN News crew, which unlike most journalists covering the war was not attached to any U.S. or British unit, had first come under fire at Iman Anas, near Basra, while driving toward the port city in two vehicles marked "Press."

Lloyd, who had reported from Iraq, Cambodia, Bosnia and Kosovo during his award-winning career, was initially wounded in the stomach. He was then shot in the head by U.S. troops after he had been picked up and put in an Iraqi minibus, the inquest heard.

His translator Hussein Othman, was also killed while French cameraman Fred Nerac, is still missing believed dead. The other cameraman Daniel Demoustier was the only one to survive.

Since the start of the Iraq war in March 2003, 118 journalists and media assistants have been killed, according to Paris-based media advocacy group Reporters sans Frontieres.

Fifty-one have been abducted, of whom five are currently being held hostage.