Gunmen opened fire on municipal street sweepers in Iraq's capital on Monday, killing one and injuring two, while a senior intelligence official died in a drive-by shooting.

A day earlier, gunmen ordered four policemen and a lawyer out their car and beheaded them near the northern town of Hawija, 150 miles north of Baghdad, said police Col. Burhan Tayeb.

The dispersed violence came as the interior minister faced calls for his dismissal because of the worsening security crisis in Baghdad and surrounding towns, mostly blamed on sectarian conflict between Shiites and Sunnis.

Police also discovered the bullet-riddled bodies of three men in the Baghdad area Monday. Two were found together with their hands and feet tied, while a third was fished out of the Tigris River, his body showing signs of torture.

Four roadside bombs and two car bombs Monday injured 11 people in various parts of the country.

One was a car bombing targeting a joint American-Iraqi checkpoint on a bridge in the northern town of Rawah. Four Iraqi soldiers were seriously wounded and three Iraqi army vehicles were destroyed, said an army lieutenant who refused to give his name.

Prime Minister Nouri al-Maliki called for defeating sectarian forces in a speech Monday.

"The power is in our hands ... and we will continue hitting terrorism and ... building Iraq brick by brick on the basis on equality and justice," he said.

Several key Iraqi parliament members are pressing to replace Interior Minister Jawad al-Bolani, who is responsible for police and paramilitary commandos at the forefront of the fight against extremists in the capital.

Al-Bolani, a Shiite, was chosen for the sensitive post after protracted negotiations among the various religious and ethnic parties within the national unity government. The interior and defense posts were filled in June, nearly three weeks after the rest of the Cabinet.

The Interior Ministry, which controls the police, and the Defense Ministry, which manages the army, are the two most important and sensitive Cabinet posts.