BAGHDAD, Iraq — Police found the bodies of four men dangling from electrical pylons today in a Baghdad Shiite slum, hours after car bombs and mortars shells ripped through teeming market streets, killing at least 58 people and wounding more than 200.

The grim scene underscored fears Sunday's bloody assault on a stronghold of radical Shiite cleric Muqtada al-Sadr would plunge Iraq into another frenzy of sectarian killing.

Bomb blasts in Baghdad, Kirkuk and Tikrit — many of them targeting Iraqi police patrols — killed at least 10 more people today and wounded more than 30. They included a U.S. soldier killed in a roadside bombing in east Baghdad, the military said. A U.S. Marine was reported killed the previous day in the western insurgent-plagued province of Anbar.

Iraqi President Jalal Talabani said terrorists bent on igniting were taking advantage of a vacuum in authority caused by tangled negotiations to form a new government.

"The way in which this bloody act was conducted leaves us with no doubt that the terrorists have targeted this peaceful neighborhood in order to ignite civil strife and stoke the fire of civil war," Talabani said in a statement. "So, it is the duty of the political groups to accelerate efforts to form the government, and the armed forces and security bodies should act swiftly to eliminate such crimes.

Addressing reporters in the Shiite holy city of Najaf, the anti-American cleric al-Sadr avoided blaming Sunni Muslims for the attacks and appealed for unity today. He instead blamed the feared terror group al-Qaida in Iraq and U.S. forces.

"Sunnis and Shiites are not responsible for such acts," al-Sadr said. "National unity is required."

Members of al-Sadr's Mahdi Army militia captured the four people found hanged in the Shiite ghetto, according to police and a member of al-Sadr's organization, Sheik Amer al-Husseini. Police collected the bodies early Monday.

"We know nothing about their nationalities but residents reported that they were arrested yesterday by Mahdi Army," said local police Lt. Laith Abdul-Aal. "Two of them were wearing explosive belts and two others had mortar tubes."

Al-Husseini identified the men as three Iraqis and a Syrian.

Iraqis had feared an attack like this one was coming, especially after al-Sadr's fighters stormed out of the slum to take revenge on Sunni Muslims and their mosques after the Feb. 22 bombing of a revered Shiite shrine in Samarra.

The attackers struck with car bombs, including a suicide driver, and mortars at the peak shopping time, destroying dozens of market stalls and vehicles.