Baghdad — Iraq's presidential council dropped its objections Wednesday to a law that helps clear the way for provincial elections that are considered key to reconciling the country's ethnic and religious factions.

The unexpected announcement by the council, made up of the country's president and two vice presidents, follows intense lobbying by U.S. officials to make the power-sharing compromises needed to solidify a recent drop in violence.

U.S. patience with Iraq's fractious politicians is wearing thin as the war enters its sixth year. But Wednesday's decision offers officials here a sign of progress, which they can use to make the case in Washington for time over the summer to assess the impact of U.S. troop withdrawals under way before pulling out more forces.

Gen. David H. Petraeus, the top U.S. commander in Iraq, and U.S. Ambassador Ryan Crocker will make their recommendations to Congress in April.

The measure, which defines the relationship between the country's 18 provinces and the central government, calls for elections by Oct. 1, 2008. Iraq's parliament approved it on Feb. 13 under a package deal that included a $48 billion national budget and an amnesty plan for the mostly Sunni Arab detainees languishing in Iraqi custody.

But the presidential council withheld its needed approval because of objections from Vice President Adil Abdul-Mahdi, a member of the main Shiite Muslim political party, the Supreme Iraqi Islamic Council. President Jalal Talabani, a Kurd, and Vice President Tareq Hashimi, a Sunni, are the other members.

The dispute centered on an article that would give the prime minister authority to ask parliament to remove a provincial governor. Abdul-Mahdi argued that the provision is unconstitutional and the authority to dismiss governors should rest with the provincial councils that select them, an aide said Wednesday.

Abdul-Mahdi's party, a strong proponent of decentralization, won control of most of the overwhelmingly Shiite south in the last provincial elections in 2005. But the party faces a growing challenge from followers of radical Shiite cleric Muqtada al-Sadr, who helped put Prime Minister Nouri al-Maliki in office.

Al-Sadr loyalists had accused Abdul-Madhi and his party of trying to delay the polls in order to hang on to power.

The council, which must unanimously agree to any legislation before it becomes law, dropped its objections after receiving assurances that parliament would consider amendments to the law, said Nasir Ani, the panel's chief of staff.

The measure now must be published in an official gazette, which is expected in the coming days. Even with approval of the law, the political blocs need to agree on rules for conducting the October election.

Most Sunni Arabs boycotted the last elections, as did al-Sadr's followers, handing a disproportionate share of local power to other factions representing the majority Shiites and to their Kurdish allies. The imbalance has been a source of mounting friction in ethnically and religiously mixed parts of the country, as well as in the Shiite south, where al-Sadr's followers are pushing for more influence. U.S. officials have said that fresh elections are essential to stave off more violence.

The number of attacks dropped late in 2007 after the U.S. military deployed 28,500 additional troops to Iraq, Sunni Muslim tribesmen rebelled against religious extremists in their areas, and al-Sadr ordered his Mahdi Army militia to stand down.

But recent suicide bombings have pushed up the civilian casualty toll as the added troops are being pulled out. Five combat brigades will be gone by the end of July, bringing the number of troops in Iraq to about 140,000 from a peak of nearly 170,000.

Petraeus has said that he would like time to assess whether the security gains can withstand further withdrawals.

Underscoring the danger, a woman with explosives hidden under her black gown attacked a police convoy Wednesday, killing five people and injuring 11 northeast of Baghdad, police said. It was the ninth suicide attack carried out by a woman so far this year.

The latest attack happened in a busy commercial district of Balad Ruz, a religiously mixed city in Diyala province. The woman stepped into the street as a convoy drove by ferrying a police captain to work, according to the provincial operations center. Two policemen were among those killed and four were injured, police said.

The U.S. military, meanwhile, announced the death of a soldier Wednesday in a vehicle rollover in Diyala. At least 3,991 U.S. personnel have died since the start of the war in 2003, according to the independent Web site icasualties.org.

North of Diyala, U.S. forces accidentally killed three Iraqi policemen and injured a fourth on the road between Kirkuk and Hawija. Iraqi police, responding to a report of a possible car bomb, drove into an area where American troops were conducting operations, said Staff Sgt. Sam Smith, a spokesman for U.S. forces in northern Iraq.

“Entering into a previously cordoned area at a high rate of speed, the Iraqi police received fire from a coalition force soldier who had perceived the vehicle as a threat,” Smith said in an e-mail. “The incident is currently under investigation.”

Special correspondents in Baghdad, Kirkuk and Mosul contributed to this report.

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