Up and down the barricaded street, soldiers and policemen loyal to al-Sadr’s Shiite rivals stood sentry, some in tan armored personnel carriers, questioning anyone they suspected of links to the populist cleric.
December 26, 2007 10:12 am Islamic Supreme Council of Iraq, Shiite Militiamen in Iraqi Army and Police, Mahdi Army, Iraq 
Radical cleric Moqtada al-Sadr is battling his Shiite rival along lines of personality, class and ideology. (By Alaa Al-marjani — Associated Press)
Sudarsan Raghavan, Shiite Contest Sharpens In Iraq - washingtonpost.com, December 26, 2007
KARBALA, Iraq — Posted at the door of Shiite cleric Moqtada al-Sadr’s office recently, a flier denounced the arrests of his followers. Up and down the barricaded street, soldiers and policemen loyal to his Shiite rivals stood sentry, some in tan armored personnel carriers, questioning anyone they suspected of links to the populist cleric.
Inside the shuttered office, five guards spoke frankly of their sense of vulnerability and weakness. Once in control of the streets of this southern city of holy sites, the Sadrists said they have been chased underground, their rivals at their heels.
The arrests of Sadr’s loyalists are part of a broader power struggle between the two most powerful Shiite factions seeking to lead Iraq: the Sadrists, who are pushing for U.S. troops to withdraw, and the Islamic Supreme Council of Iraq, the Bush administration’s main Shiite ally. Given the nation’s majority-Shiite population, this intensifying confrontation could play a major role in deciding Iraq’s future.