Strong explosions shook central Baghdad early Sunday, and fighting erupted on a major street in the heart of the city near the U.S.-guarded Green Zone (search). Five civilians died and 48 were injured in the violence, Iraqi officials said.

In western Baghdad, a car bomb killed two Iraqi police officers on patrol, the Interior Ministry said. Insurgents have regularly attacked police because they are seen as being collaborators with American troops.

Rocket and mortar fire erupted about 5:30 a.m. and continued into the morning. Several rounds landed in the Green Zone, raising clouds of black smoke and triggering warning sirens.

The rattle of heavy machine-gun fire echoed through Haifa Street, located on the western side of the Tigris river near the Green Zone and a "no go" area for international forces. A Bradley fighting vehicle caught fire and children climbed on top, cheering and dancing beside the flames after the Americans left.

U.S. soldiers fired from behind walls and trees along Haifa Street (search) while several hundred residents milled about to watch the battle. A military spokesman, Maj. Phil Smith of the 1st Cavalry Division, said the Bradley was apparently hit by a roadside bomb. Four soldiers were slightly hurt, he said.

The battle on Haifa Street lasted for about 90 minutes. Afterward, as a column of a dozen Bradleys and armored personnel carriers left the scene, residents shouted "Allahu Akbar," or "God is Great."

A low-flying helicopter later swooped down over the burning Bradley and the cheering crowd, who dispersed following a series of explosions, possibly caused by stun grenades.

"The battle began before daylight," said Mohammed Salah, 19, whose third-floor family apartment overlooks the area where most of the fighting took place. "We all sat on the floor in a room away from the windows and waited until it was over."

Scattered shoes, pools of fresh blood and debris scattered the roadway after the morning violence. Five people were killed and 48 were injured, said Health Ministry official Saad al-Almili.

The early morning explosions followed a late-night barrage that rattled the capital. Three or four projectiles — believed to be either mortar shells or rockets — slammed into apartment buildings across the street from the Palestine and Sheraton hotels, where many international journalists are based.

Col. Adnan Abdul-Rahman, an Interior Ministry official, said there were no reports of casualties. Earlier, mortars or rockets exploded near the Green Zone and at a U.S. base in northern Baghdad. No casualties were reported.

Meanwhile, an audiotape purportedly by key terror suspect Abu Musab al-Zarqawi, boasted that Islamic holy warriors have humiliated the U.S.-led coalition in Iraq. It was impossible to verify the authenticity of the audiotape, which surfaced Saturday, the third anniversary of the Sept. 11 terror attacks.

In Basra, Iraq's major southern city, a bomb exploded outside a Saddam Hussein palace now housing a U.S. consular office. One person was killed and two were wounded, police said. The victims were believed to be Iraqis.

In Baghdad, a U.S. warplane carried out an airstrike against militants loyal to rebel cleric Muqtada al-Sadr during a battle in the sprawling Sadr City slum.

The plane fired on militiamen manning a machine gun, said U.S. Capt. Brian O'Malley of the 1st Brigade Combat Team. Residents reported that gunfire rocked the city before the attack; there was no word on civilian casualties.

"They spotted the team from the air ... and they engaged and destroyed the team," O'Malley said.

Elsewhere, insurgents kidnapped the family of an Iraqi national guard officer and burned his home northeast of the capital, Iraqi authorities said Saturday.

Kidnappers seized the wife and three children of Col. Khalis Ali Hussein on Wednesday, said Maj. Gen. Walid Khalid, the head of the Diyala provincial police force.

The incident in Khalis, 40 miles northeast of Baghdad, was the latest act of intimidation against security forces cooperating with the U.S. military. Insurgents consider the Iraqi police and security personnel to be collaborators.

Also in Khalis, gunmen killed a national guard officer, his son and their driver in a drive-by shooting Saturday, Khalid said. The men were traveling to Baghdad at the time.

North of Baghdad, more residents fled Tal Afar amid a siege of the largely ethnic Turkish city, where Iraqi and American forces say they are trying to root out hundreds of militants and restore government control, the military said.

The extent of the exodus was not immediately clear, but the military said the International Red Crescent was offering help and medical care to the displaced.

The campaign was part of a new American effort to restore government authority to lawless areas of the country — either through negotiation or by force.

The U.S. military said Iraqi police raided a house north of Baqouba and arrested two Egyptian men, confiscating a large cache of weapons, including bomb-making gear.

In Saturday's audiotape, the speaker noted recent battles between American forces and militiamen in the holy city of Najaf, indicating the recording was made recently.

The voice was similar to that of previous recordings of al-Zarqawi and used a similar style of rhythmic speech. There was no reference to the Sept. 11 attacks in the tape, titled "Where is the honor?"

"The holy warriors made the international coalition taste humiliation ... lessons from which they still are burning," the speaker said. His speech lasts about 25 minutes.