BAGHDAD - A Canadian working for the U.S. military in Iraq has been charged with aggravated assault under military law, the first such prosecution since the Vietnam War, the U.S. command said Saturday.

Alaa (Alex) Mohammad Ali, who holds dual Iraqi-Canadian citizenship, is the first person to face such criminal charges since Congress in 2006 gave the military authority to prosecute crimes committed by civilians working for the armed forces, a U.S. statement said.

Ali, a U.S. army translator, is accused of stabbing another contractor during a fight Feb. 23 at a base near Hit, a town 135 kilometres west of Baghdad in Anbar province, the statement said. The victim was wounded in the chest and sternum.

Ali, who was assigned a military lawyer, has been in detention since Feb. 29 at a stockade near Baghdad International Airport. A hearing has been scheduled for Thursday, the statement said.

The hearing is similar to a grand jury in the civilian justice system. A senior army officer will hear evidence and make recommendations about the charge.

The recommendations will then be forwarded to Lt.-Gen. Lloyd J. Austin, commanding officer of the Multinational Corps, who will decide whether to order a trial, the statement said.

Col. Bill Buckner, a military spokesman, said it is the first time since 1968 that a civilian working for the U.S. military has been charged under military law.

In 2006, Senator Lindsey Graham added a measure to a defence spending bill that made civilians working for the U.S. military in a "contingency operation'' subject to courts martial.

The provision was intended to close the legal loophole that made it difficult to successfully prosecute such individuals in conflicts were Congress had not formally declared a state of war.

There are more than 160,000 contractors working in Iraq and some 36,000 in Afghanistan _ about the same number of troops in those regions. They perform numerous tasks including supplying food and water, building barracks, providing armed security and gathering intelligence.

The contractors have operated in a legal grey area because officials exempted them from prosecution in Iraqi courts in 2004. It has also been unclear whether they could be charged in courts in the United States.

Eugene Fidell, president of the National Institute of Military Justice, a Washington-based non-profit organization, said the case "tests the outer limits of military jurisdiction.''

"Questions will be raised about whether it is constitutional for a civilian to be tried in a military court,'' Fidell said.

He added that non-binding international human rights law discourages trying civilians in military courts but said he would be surprised if the U.S. Supreme Court ruled this case unconstitutional.

Fidell suggested that the outcome could have implications for other civilians involved with U.S. military operations, possibly including CIA personnel, embedded reporters or security contractors, like those provided by Blackwater.

Iraqis were outraged over a Sept. 16 shooting in which 17 Iraq civilians were killed in a Baghdad square by contractors working for Blackwater, one of the largest private military companies which has a contract to protect the U.S. diplomats in Iraq.

Blackwater said its guards were responding to an attack on an American diplomatic convoy, but Iraqi investigators concluded the shooting was unprovoked.

During the war in Vietnam, several civilians working for the U.S. armed forces were charged with violations of military law. Although there were several convictions these were eventually struck down by the U.S. Supreme Court, which has overturned all civilian convictions under military law in the past half century.