BAGHDAD, Iraq - Some 5,000 U.S. Marines, British troops and Iraqi forces launched a new offensive Tuesday aimed at clearing a swath of insurgent hotbeds across a cluster of dusty, small towns south of Baghdad.
The series of raids and house searches was the third large-scale military operation this month aimed at suppressing Iraq's Sunni Muslim insurgency ahead of crucial elections set for Jan. 30.
The assault aims to stem an increase of violence in an area that has been notorious for months as a danger zone. Car bombings, rocket attacks and ambushes have surged in recent weeks - likely in part due to guerrillas who slipped out of the militant stronghold of Fallujah, according to commanders.
Despite the series of offensives, violence continued unabated. Masked gunmen shot to death a Sunni cleric Tuesday in the second such attack against a member of the influential Association of Muslim Scholars, which has called for a boycott of the national elections.
The cleric, Sheik Ghalib Ali al-Zuhairi, was killed as he left a mosque after dawn prayers in the town of Muqdadiyah, 60 miles north of Baghdad, police said.
His assassination occurred a day after another prominent Sunni cleric was killed in the northern city of Mosul - Sheik Faidh Mohamed Amin al-Faidhi, who was the brother of the association's spokesman. It was unclear whether the two attacks were related.
Insurgents hit a U.S. convoy with a roadside bomb near the central Iraq city of Samarra, prompting the Americans to open fire, killing an Iraqi, hospital officials said. Mortar rounds aimed at a nearby U.S. military base injured two children.
Also Tuesday, a top aide to radical Shiite cleric Muqtada al-Sadr accused the government of violating terms of the August agreement that ended an uprising by al-Sadr's followers in Najaf.
Ali Smeisim, al-Sadr's top political adviser, made no explicit threats but his remarks raised the possibility of a new confrontation with al-Sadr's Mahdi Army militia, which fought heavy battles against the Americans and their Iraqi allies in April and August.
Smeisim accused the government of breaking an agreement not to arrest members of al-Sadr's movement and to release most of those being held in detention. "Iraqi police arrested 160 al-Sadr loyalists in Najaf four days ago," he said.
The joint military operation kicked off with early morning raids in the town of Jabella, 50 miles south of Baghdad, as Iraqi and American troops, backed by jets and helicopters, swarmed into the region known as the "triangle of death."