A suicide truck bomber struck the provincial headquarters of an Iraqi police commando force north of Baghdad on Monday, killing at least 10 troops and wounding 18 others, police said.

At least 20 others were killed elsewhere in the country including three civilians during fighting that broke out when Iraqi and U.S. forces raided a Shiite militia stronghold in Baghdad early Monday. Residents said military aircraft were used in the raid, ostensibly to capture extremists suspected of running torture cells. One U.S. soldier was injured.

Prime Minister Nouri al-Maliki condemned the raid. "I was very angered and pained," he said on national television, noting he had prohibited such operations "because we are in a national reconciliation process."

The force used was disproportionate to the mission's objective, he said. "That's why I have vowed that this won't happen again. I am so sorry for what happened."

Al-Maliki also promised the family of each killed person a grant of 2 million dinars (US$1,360), and 1 million dinars (US$700) for the injured, said the prime minister's adviser, Mohammed Salman.

The suicide bomber drove his truck filled with apples and bananas through razor-wire barricades into the two-story building housing the offices of the Interior Ministry's police commandos in central Samarra, police Capt. Laith Mohammed said.

He said the truck's explosion killed 10 commandos and injured eight in addition to injuring 10 civilians.

The building was virtually leveled, said policeman Mohammed Ali, who went to the scene with an ambulance after the attack. He said three houses nearby were severely damaged and three cars were destroyed.

Samarra, 60 miles north of Baghdad, was the site of a bomb attack that destroyed a revered Shiite shrine on Feb. 22, setting off a wave of deadly sectarian attacks that pushed the country to the brink of civil war.

The bombing was the latest in a series of attacks across central and northern Iraq in recent days that have tested the capabilities of Iraq's U.S.-trained security forces.

In Baghdad, sounds of heavy gunfire and explosions rattled the Sadr City district about 1 a.m. local time Monday and persisted for more than an hour. Iraqi government television and aides to radical Shiite cleric Muqtada al-Sadr said U.S. aircraft attacked buildings in the area.

Col. Hassan Chaloub, police chief of Sadr City, said three people including a woman and a 3-year-old girl were killed and 12 injured in the fighting. He said three cars and three houses also were destroyed.

The United States recently reinforced its troop strength in the city to try to reclaim the streets from militias — which include al-Sadr's Mahdi Army.

Gen. George Casey, the top U.S. commander in Iraq, said Monday he discussed with Iraq's President Jalal Talabani a security plan to bring "fundamental change to the security situation in Baghdad."

"There is a comprehensive plan to change the situation significantly prior to Ramadan," the Islamic holy month that begins late September, he said without elaborating.

The U.S. military recently reinforced its troop strength in the city to try to reclaim the streets from militias.

Addressing concerns about the rising power of Shiite militias, Talabani said he has written to al-Sadr "to control those elements of the Mahdi Army" who take "illegal actions." He also said he told Casey that "it is in nobody's interest to have confrontations with the Sadrists."

Talabani rejected suggestions that the country was sliding toward civil war.

"Sunnis and Shiites are intermingled and their leaders are opposed" to civil war, he said.

In northern Iraq, police fired in the air to disperse hundreds of stone-throwing demonstrators in Darbandikhan, injuring at least 11 people, provincial government official Othman Haji Mahmoud said. The protesters were demanding better living conditions such as electricity and fuel, the second such protest in two days in the area.

In other violence Monday, 17 people were killed or their bodies found. Among those killed were five people in a barbershop in Baghdad who were sprayed with gunfire by unidentified assailants, and four insurgents killed by U.S. forces while they were planting roadside bombs west of Baghdad, the U.S. military said in a statement.