Tens of thousands of Iraqi and U.S. troops have spread across Baghdad in a major security crackdown in the Iraqi capital.

The troops, with tanks, armored units and air support, set up checkpoints throughout the city. Iraqi Prime Minister Nouri al-Maliki also ordered extended curfews and a ban on vehicle traffic during Friday prayer hours. That's a time when insurgents have launched many attacks.

As the operation got underway Wednesday, Mr. Maliki said he is ready to hold talks with some insurgent groups ready to join the political process. But he said he will not negotiate with people who have blood on their hands.

Despite the increased security, Iraqi police say a car bomb killed two people in Baghdad and wounded six others.

South of the capital, in Basra, a crowd set fire to part of the Iranian consulate. They were mostly followers of a local Shi'ite cleric and they apparently were upset about an Iranian television program that they felt insulted the cleric. There were no reports of casualties.

Meanwhile, the new leader of the al-Qaida in Iraq terrorist group, Abu Hamza al-Muhajer, has vowed to avenge the killing of his predecessor, Abu Musab al-Zarqawi.

Some information for this report was provided by AFP, AP and Reuters.