Police said three people, including a woman and a child, were killed in the raid, which the US command said was aimed at "individuals involved in punishment and torture cell activities."

One US soldier was wounded, the US said.

Al-Maliki, a Shiite, said he was "very angered and pained" by the operation, warning that it could undermine his efforts toward national reconciliation.

"Reconciliation cannot go hand in hand with operations that violate the rights of citizens this way," al-Maliki said in a statement on government television. "This operation used weapons that are unreasonable to detain someone - like using planes."

He apologized to the Iraqi people for the operation and said "this won't happen again."

Friction between the US military and the Iraqi government emerged as the US military kicks off a military operation to secure Baghdad streets after a surge in Sunni-Shiite violence - much of it blamed on al-Sadr's militia.

Al-Sadr has emerged as a major figure in the majority Shiite community and a pillar of support for al-Maliki. The prime minister's remarks underscore the difficulties facing the Americans in bringing order to Baghdad at a time when Iraqis are increasingly resentful of the presence of foreign troops.

U.S. officials are equally frustrated by the slow pace of reconciliation and what they feel is the reluctance of politicians to reach consensus among Iraq's religious and ethnic groups on the future of the nation.

After the Sadr City attack, President Jalal Talabani, a Kurd, met with the top U.S. commander in Iraq, Gen. George W. Casey Jr., to discuss security operations in Baghdad. Talabani said he told Casey "it is in no one's interest to have a confrontation" with al-Sadr's movement.

Speaking to reporters after the meeting, Casey made no mention of al-Sadr but said he had discussed plans with Talabani to bring "fundamental change to the security situation in Baghdad."

Casey said he hoped the new operation would "change the situation significantly prior to Ramadan," which begins in late September.

"To do that, it will take the cooperation not only between the Iraqi security forces and the coalition but with all of the people in Baghdad working together to combat terrorism," Casey said. "All the security operations are designed to protect the population. And if the people of Baghdad can cooperate with the security forces, that can happen very quickly."

But the public position taken by al-Maliki and Talabani signaled serious differences between Iraqi politicians and both US and Iraqi military officials on how to restore order and deal with armed groups, many of which have links to political parties.

U.S. officials have spoken of morale problems in senior ranks of the Iraqi security services because of what they believe is insufficient political support by the country's divided civilian leadership.

The suicide attack in Samarra targeted the regional headquarters of Interior Ministry's elite commando force, a heavily Shiite organization which many Sunnis have accused of human rights abuses against Sunni civilians.

The blast heavily damaged the two-story building as well as three nearby houses, said policeman Mohammed Ali, who escorted an ambulance to the scene.

Samarra, 60 miles north of Baghdad, was the site of the February bombing of a Shiite shrine that set off the wave of tit-for-tat sectarian killings and kidnappings that have pushed the country to the brink of civil war.

In other violence Monday, five people were killed and six others wounded when a roadside bomb exploded near their minivan near Khalis, about 45 miles northeast of Baghdad, police said.

One person was killed when truck bomb went off in Khan Bani Saad, 24 miles northeast of Baghdad, police said.

Bodies of nine people were brought to the regional morgue in Kut, police and health officials said. Seven of the nine bodies were Iraqi soldiers.

Other victims included five men shot dead in a Baghdad barbershop and four insurgents killed by U.S. troops west of Baghdad, police and US officials said.