U.S. and Iraqi forces have raided seven mosques believed to be providing support for insurgents in the restive western city of Ramadi.
The U.S. military says the operation is part of a joint effort to search for known terrorists and insurgents, as well as for illegal weapons.
Witnesses say soldiers arrested Sheikh Abdul Aleim Saadi, the region's top Sunni Muslim cleric.
Also Tuesday, the United States said its warplanes conducted two strikes on buildings used by Abu Musab al-Zarqawi's terror network in the western city of Fallujah.
Abu Musab al-Zarqawi has claimed responsibility for numerous car bombings, kidnappings and beheadings in Iraq.
In the south, an explosion rocked the city of Basra. It was not immediately clear what caused the blast. There were no reports of casualties.