A platoon leader accused of ordering soldiers to force two Iraqis into the Tigris River (search) at gunpoint pleaded guilty to a pair of assault charges.

Army 1st Lt. Jack Saville (search) also pleaded guilty Monday to obstruction of justice and dereliction of duty, and could face up to nine years in military prison under a plea deal.

Meanwhile, he pleaded not guilty to conspiracy, making a false statement and involuntary manslaughter — and under the plea agreement won't be tried on those charges.

He will be tried beginning Tuesday on an aggravated assault charge involving an earlier case in Balad, where an Iraqi was detained and thrown in the Tigris.

Saville, a 25-year-old West Point graduate, is accused of ordering troops to push two curfew violators into the river near Samarra. The government says Zaidoun Hassoun (search), 19, drowned.

Defense lawyers contend Hassoun is still alive, and a judge has granted a defense request to exhume the body, identify it and determine the cause of death. It's unclear if the exhumation has already taken place.

Saville pleaded guilty to aggravated assault on Zaidoun Hassoun and assault by battery on his cousin, Marwan Hassoun.

The obstruction of justice charge was for concocting a lie — that soldiers had left the two Iraqis along the road instead of forcing them into the river.

The dereliction of duty charge was for an incident when Saville failed to challenge an illegal order to kill certain Iraqis suspected of being involved in an attack that killed an American soldier.

Saville told the court-martial he got the order from Capt. Matthew Cunningham.

Cunningham was one of three commanders linked to the drowning case who were given nonjudicial punishments for allegedly conspiring to impede a homicide investigation. The Army said the punishment did not include jail time.

In January, Saville's co-defendant, Sgt. Tracy Perkins, was convicted of two counts of aggravated assault, obstruction of justice and assault consummated by battery. He was sentenced to six months in military prison and his rank was reduced to staff sergeant.

Perkins and Saville are part of the 3rd Brigade Combat Team out of Fort Carson, Colorado, which is part of the 4th Infantry based at Fort Hood.

Also Monday, the British Ministry of Defense announced that a soldier in the Royal Air Force accused of killing five Iraqi civilians by driving dangerously in Iraq will face a court-martial next month.

James A. Bowskill is accused of being involved in the killings on a road near Basra on Feb. 3, 2004, the ministry said. Neither his rank nor age were released.

Britain, Washington's top ally in the U.S.-led coalition, has about 8,000 troops in Iraq, mostly based in or near Basra in the south.