A U.S. soldier was sentenced to three years in prison for killing a severely wounded Iraqi teenager, the military said Saturday, while insurgents staged attacks in several cities, killing at least 10 Iraqis, including three police colonels, and wounding 14 U.S. soldiers.

The American forces were wounded in separate attacks in northern Iraq, including a car bomb blast that injured eight troops and led to a U.S. warplane dropping a 500-pound bomb on an insurgent position in Mosul (search), 225 miles northwest of Baghdad.

Staff Sgt. Johnny M. Horne Jr. (search), 30, of Wilson, N.C., pleaded guilty on Friday to one count of unpremeditated murder and one count of soliciting another soldier to commit unpremeditated murder.

His sentencing included a reduction in rank to private, forfeiture of wages and a dishonorable discharge.

The charges relate to the Aug. 18 killing of a 16-year-old Iraqi male found in a burning truck with severe abdominal wounds sustained during clashes in Baghdad's Sadr City, an impoverished neighborhood that was the scene of fierce fighting between U.S. forces and Shiite rebels loyal to anti-U.S. cleric Muqtada al-Sadr (search).

A criminal investigator had said during an earlier hearing that the soldiers decided to kill him to "put him out of his misery."

A jury-like panel of seven service members late Friday sentenced Horne — who is attached to Company C, 1st Battalion, 41st Infantry Regiment, based in Fort Riley, Kan. — after about four hours of deliberations, the military said on Saturday.

In fresh violence, a military convoy was struck by a car bomb Saturday morning in Mosul, killing an Iraqi civilian but causing no U.S. casualties.

A second car bomb attack hours later wounded eight U.S. soldiers after they uncovered a weapons cache in Mosul. Militants then fired mortars, rocket-propelled grenades and machine guns.

"The commanders on the ground felt the attack was heavy enough to call in close air support, and a fighter jet dropped a 500 pound bomb on an insurgent position," military spokeswoman Capt. Angela Bowman said.

Elsewhere, a suspected suicide car bomber wounded two U.S. soldiers in Beiji, 155 miles north of Baghdad, while two more were wounded in a car bomb blast near Kirkuk, about 60 miles to the north.

Two more U.S. soldiers were wounded by a roadside bomb outside of Hawija, near Kirkuk.

U.S. soldiers also were ambushed late Friday in Ramadi, a hotbed of anti-American violence 70 miles west of Baghdad, by insurgents firing rocket propelled grenades and small arms from the city's hospital and medical academy, the Marines claimed in a statement Saturday.

Insurgents hid inside the Ramadi General Hospital and Medical College and in nearby areas waiting for the soldiers to move into their ambush zone, said Capt. Bradley Gordon, spokesman for the 1st Marine Division of the 1st Marine Expeditionary Force.

"Some of the muzzle flashes of insurgent firing positions were observed as originating from windows within the hospital," he said.

Officials from both the Ramadi General Hospital and Medical College, rejected the U.S. claims that they were used in the ambush, but said fighting occurred nearby.

Two Iraqi civilians, including judge Omar Abdul Aziz Rashid, were killed during fighting, but no U.S. casualties were reported.

"It was very hard to identify my husband's body, because it was charred inside the car," the judge's wife, Dr. Eman Abdul Qadre, said.

Separately, police on Saturday found seven bodies apparently killed several days ago and dumped near a highway about 20 miles west of Ramadi.

Lt. Col. Ziyad al-Jubouri said the seven didn't look Iraqi, while a hospital official said two Sudanese men asked about the bodies at the morgue. The Sudanese Embassy said it has heard of the grisly finds and sent an official to investigate.

U.S. forces also blew up a large cache of confiscated weapons in Ramadi late Friday.

Militants, who are predominantly from Iraq's Sunni Muslim minority, also continued their attacks against Iraqi security forces and members of the country's majority Shiite community.

Gunmen killed two Iraqi policemen, including a colonel, in an ambush north of Beiji on Saturday, U.S. military spokesman Maj. Neal O'Brien said.

Two other police colonels were killed in Baghdad's southwestern Saidiyah neighborhood Saturday morning after being ambushed by two cars carrying eight gunmen, an official said on condition of anonymity. The colonels were assigned to the Interior Ministry's criminal intelligence department.

Another two police officers were killed, including one captain, and two more wounded by militants while patrolling Baghdad's northern Azamiyah suburb late Friday, police Lt. Mohammed al-Obeidi said.

In the nearby Shula neighborhood, Shiite cleric Salim al-Yaqoubi was killed by gunmen near his house early Saturday, a police spokesman said.

A second Shiite cleric, Sheik Ammar al-Jibouri, was slain on Friday near Mahmoudiya, about 25 miles south of Baghdad, as he was driving to the capital. Al-Jiborui once headed a religious court of followers of anti-U.S. cleric Muqtada al- Sadr in the southern holy city of Najaf.

Al-Sadr aide Sheik Ali Smesim said al-Jibouri's killing was aimed at "flaring a sectarian war between Iraqis."

In the central Iraqi city of Samarra, a mortar shell slammed into a car late Friday, killing one occupant and injuring another, U.S. military spokesman Master Sgt. Robert Powell said.

Horne was among six Fort Riley soldiers charged with killings in recent months — two for slayings in Kansas and four for deaths in Iraq. Staff Sgt. Cardenas J. Alban, 29, of Inglewood, Calif., is charged along with Horne in the teenager's killing and is awaiting a court-martial hearing.

Two other soldiers from the same unit this week faced Article 32 hearings — the military equivalent of a grand jury hearing — over a Sadr City killing in August.

Human rights groups have condemned the illegal killings of Iraqis — either civilians or wounded fighters — by the U.S. military, saying such acts amount to violations of international humanitarian rights and should be dealt with as war crimes.

Critics also say poor understanding by young U.S. troops of the rules of military engagement leads to the killing of civilians.

"It doesn't help you win the hearts and minds of the public if you put a bullet in their hearts and another in the minds," said Mark Garlasco, senior military analyst for Human Rights Watch.