The US military announced that a new offensive 'on a scale not seen in Iraq before' will be launched against militants.
It comes as an Iraqi Interior Ministry official said about 1,000 Iraqi civilians, security personnel and militants had died in the past week alone.
A command center overseeing the crackdown is being put in place today.
The center will be overseen by an Iraqi officer, General Abboud Gambar, a Shia who fought US forces in the 1991 Gulf War.
Top Sadr official killed in Iraq raid Hat tip: Rufus
1:22 a.m. February 5, 2007
BAGHDAD – Iraqi and U.S. forces killed a top official of radical Shi'ite cleric Moqtada al-Sadr's organisation in a raid on his home north of Baghdad on Sunday, calling him a 'rogue leader' of Sadr's Mehdi Army militia.
An official in Sadr's political office, Abdul-Mehdi al- Matiri, called the killing of Khadhim al-Hamadani in the village of Huweidar near Baquba an 'assassination'.
The U.S. military said in a statement that Hamadani had reportedly been responsible for attacks on U.S. and Iraqi troops and was believed to have 'facilitated and directed numerous kidnappings, assassinations and other violence'.
They said two Iraqi soldiers shot him dead after storming a building and finding him armed with an assault rifle and 'displaying hostile intent'.
Iraqi police said Hamadani had been the leader of Sadr's political office in Diyala province. In their report on the incident, they said he was shot when he tried to flee.
But Sadr official Matiri said he had not been shot but stabbed with a bayonet.
Also on Sunday, gunmen killed Sheikh Khalil al-Maliki, a local leader of Sadr's movement, in a drive-by shooting in the southern city of Basra, police said.
Iraqi and U.S. forces have seized or killed hundreds of followers of Sadr in recent weeks in a crackdown on militias in the capital and southern Iraq. British forces have also targeted Sadr officials in Basra, detaining a number in raids.
Senior Shi'ite officials close to Prime Minister Nuri al- Maliki's government say U.S. and Iraqi forces are mounting a campaign to seize leaders in the movement in an effort to quell sectarian violence that is pushing Iraq toward civil war.
Sadr himself, a populist young preacher with a mass following, has publicly distanced himself from violence blamed on his Mehdi Army supporters, whom the Pentagon has called the biggest threat to the security of Iraq.
Prime Minister Maliki, a Shi'ite Islamist, partly owes his position to support from Sadr's political movement and has been criticised by Washington for failing to disarm the Mehdi Army.
As he and U.S. commanders prepare to deploy Iraqi and American reinforcements in a major security crackdown in Baghdad, Maliki has promised to quell Shi'ite militias as well as Sunni insurgents.
He said in January that 400 Mehdi Army members had recently been arrested in southern Iraq.
(Additional reporting by Mariam Karouny in Baghdad)