3-Day Curfew Imposed In Baghdad

Iraq's government imposed a three-day, 24-hour curfew in Baghdad yesterday night as it struggled to prevent a slide toward civil war with supporters of the radical cleric Moqtada al-Sadr.

The action came after a third day of violence that started with insurgents blowing up a major oil pipeline near Basra. Fighting raged between Shiite gunmen and Iraqi security forces in the capital and in towns across the restive south.

For the first time, American forces were drawn into the conflict as they helped the inexperienced troops.

In Baghdad, thousands of Shiites marched in support of Mr. Sadr and called for the resignation of Nouri al-Maliki, the Iraqi prime minister, whose drive to purge Basra of Shiite militias sparked the unrest.

Repeated rocket attacks on Baghdad's diplomatic Green Zone, the seat of the Iraqi government, left huge plumes of smoke drifting over the Tigris river.