Baghdad ? Dozens of Iraqi legislators walked out of parliament Thursday to protest parts of a draft law that would lay out rules for provincial elections later this year, marking another potential setback for U.S.-backed proposals to ease Iraq’s sectarian rifts.

Radical Shiite cleric Muqtada al-Sadr, meanwhile, warned his fighters to stick with his cease-fire order after U.S. and Iraqi raids in Baghdad’s Sadr City, the main Shiite district and bastion of al-Sadr’s Mahdi Army militia. The sweeps detained 15 suspected militants and left one person dead.

The U.S. military said troops targeted “criminal elements” responsible for attacks with mortars and powerful roadside bombs that the Pentagon links to Iranian aid.

In parliament, the walkout postponed a planned vote on the measure on redistributing power in Iraq.

The last time Iraqis voted for local officials was January 2005, when nationwide elections ushered in representational government across Iraq for the first time in modern history.

But many Sunni Arabs boycotted the polls, giving Iraq’s majority Shiites and minority Kurds a much bigger share of power. The U.S. hopes the new elections will empower the Sunni minority and blunt support for the insurgency.