With Psalms and a 21-gun salute, soldiers hailed two fallen comrades from the 1st Battalion 22nd Infantry Regiment in a memorial service Thursday at one of Saddam Hussein's palaces.

Spc. James Powell, 26, of Mark Center, Ohio, was killed Sunday when his Bradley armored vehicle struck a land mine near Beiji, 30 miles north of Tikrit.

Spc. Donald L. Wheeler, 23, of Concord, Mich., was killed in an attack Monday in downtown Tikrit, when a rocket-propelled grenade hit his vehicle.

Tikrit, Saddam's hometown 120 miles north of Baghdad, lies at the heart of the Sunni Triangle, a region stretching north and west of the Iraqi capital where most of the attacks against U.S. soldiers have taken place.

Several hundred soldiers, including those of Wheeler's Charlie Company and Powell's Bravo Company, gathered at the downtown palace for the somber ceremony. The soldiers' units are part of the 4th Infantry Division (search), which controls a large swath of northern Iraq, is based in Tikrit.

The two soldiers' helmets were placed together with their nametags over their rifle butts, next to their boots on a small podium adorned with the U.S. flag and the regimental banner. Medals, including the Bronze Star (search) and the Purple Heart (search), were awarded posthumously to Wheeler and Powell, and placed next to their rifles.

"We mourn their loss; we honor their sacrifice," said Lt. Col. Steve Russell, the battalion commander.

"We will finish their mission. As long as Regulars draw breath, we shall not forget them," Russell said, invoking the regiment's motto: "Regulars by God."

Company commanders recounted how Powell had volunteered for a combat mission although he was due for home leave within days, and talked of Wheeler's "contagious smile and boundless enthusiasm."

In full battle gear, the troops stood in formation as the two soldiers' names were called out three times — with no response — in a ceremonial roll-call. A bugler played taps.

Surrounded by Bradley fighting vehicles and Abrams tanks, a soldier sang "America the Beautiful" and "Amazing Grace."

Tears streaming down their cheeks, the troops then filed one by one by the podium to pay their respects.

"I shall always remember him, a big kid who gave everything he had on that dusty day," Lt. Jason Price, of Troy, Ala., said of Wheeler. "It's difficult to say goodbye."

Maj. Gen. Roy Odiero, the 4th Infantry Division commander, laid a division coin for excellence by their medals.

"They gave their lives for their country," Odiero told reporters after the ceremony. "These are all dedicated Americans who love their country, who are here."

In Basra, 48-year-old Iraqi doctor, Haidar al-Baaj, was shot in the back of the head and killed as he was entering his private clinic, hospital officials said Thursday. The officials and members of al-Baaj's family said he had been threatened in the past two months for cooperating with authorities of the U.S.-run coalition.

British military spokesman Capt. Hisham Halawi confirmed a doctor was killed but did not provide further details.

In other developments, a 4-year-old girl died in Tikrit from injuries sustained in an explosion after a bomb went off Thursday just outside the U.S. Army base, military officials said. Her 12-year-old sister was critically injured in the blast.

Channar Abbas and her sister, Zenab, were playing on the street when the explosion occurred.

Soldiers at the U.S. base said they believed the homemade bomb was intended for two armored vehicles that had passed down the same road minutes before.

Lying at the emergency ward in the town's general hospital, eyes covered in blood-soaked bandages and a drain tube out of her chest, Zenab Abbas was conscious but screaming for her mother. Her 8-year-old brother was sitting at her side, holding her hand.

Near the northwestern Iraqi city of Hadeetha, an explosion damaged an oil pipeline, causing a fire and further hampering the country's oil export capabilities, an Oil Ministry official said.

The explosion ripped open part of the main pipeline running from the northern oil fields to the Doura refinery and the Mussayab power plant, said the official, who spoke on condition of anonymity. The extent of the damage was unknown, as firefighters were still trying to put out the flames, he said.

It was not clear whether the explosion was the work of saboteurs. There have been many attacks on pipelines in the region, complicating the U.S. rebuilding effort.

L. Paul Bremer, the U.S. civilian administrator for Iraq, has said the country is losing $7 million a day because of the closure of the export pipeline to Turkey. The line reopened for three days in September for the first time since the war. Three bombings forced its closure.

Iraq is exporting an average of 1 million barrels of oil a day, all from the southern oil fields.