Iraq Faces Shiite Crisis

BAGHDAD - Iraq's leaders faced their gravest challenge in months Tuesday as Shiite militiamen loyal to anti-American cleric Muqtada al-Sadr battled for control of the southern oil capital and unleashed rockets on the U.S.-protected Green Zone in Baghdad.

Armed Mahdi Army militiamen appeared on some Baghdad streets for the first time in more than six months, as al-Sadr's followers announced a nationwide campaign of strikes and demonstrations to protest a government crackdown on their movement. Merchants shuttered their shops in commercial districts in several Baghdad neighborhoods.

Although all sides appeared reluctant to trigger a conflagration, Brig. Gen. Ed Cardon, assistant commander of the U.S. task force operating south of Baghdad, said the situation in the south was "very complicated" and "the potential for miscalculation is high."

The burgeoning crisis - part of an intense power struggle among Shiite political factions - has major implications for the United States. An escalation could unravel the cease-fire which al-Sadr proclaimed last August. A resumption of fighting by his militia could kill more U.S. soldiers and threaten - at least in the short run - the security gains Washington has hailed as a sign that Iraq is on the road to recovery.

The confrontation will also test the skill and resolve of Iraq's Shiite-led government in dealing with Shiite militias, with whom the national leadership had maintained close ties.

Underscoring the serious stakes at play, Prime Minister Nouri al-Maliki, a Shiite, remained in the southern city of Basra to command the security operation. Sweeps were launched at dawn to rid the city of militias and criminal gangs that ruled the streets even before the British handed over control to the Iraqis in December...........