Iraqi women line up to buy rationed cooking oil Saturday in the Dora neighborhood, Baghdad.

Baghdad ? A potential security crisis loomed in troubled Diyala province Saturday as significant numbers of a U.S.-funded force of Sunni fighters left their posts, demanding the ouster of the provincial police chief.

“You can imagine what danger will face the region in the next days,” said Abu Talib, the commander of 2,000 to 3,000 so-called Sons of Iraq. His fighters, many of them former insurgents, turned against al-Qaida in Iraq last year under the Sunni Awakening banner.

A street commander, Khalid Khalidi, said nearly half of the checkpoint guards and patrolmen have walked off the job, and Talib said they might pull out in even larger numbers if provincial police chief Maj. Gen. Ghanim Quraishi is not ousted. Talib and his men, who are paid by the U.S. military, accuse the Shiite police chief of brutality against Sunnis.

Their ire boiled over, they said, after the rape, kidnapping and murder of two Sunni women two weeks ago, allegedly by men wearing police uniforms. Aides to the police chief said he was unavailable for comment.

For much of the past year, Diyala has been the deadliest region for U.S. forces battling the militants who have found refuge in its urban center and isolated villages. The province is a strategic crossroads, providing access to Baghdad, Iran and insurgent strongholds in northern Iraq.

Sunni fighters first turned against al-Qaida in Iraq in the country’s western al-Anbar province, and the U.S. military successfully cultivated more forces throughout the country. They have earned significant credit since from the military for the subsequent downturn in violence.

U.S. military officials, who have acknowledged that they do not have the troop strength to improve security in the province without the Sons of Iraq, said they were hoping for a speedy resolution.

“We are concerned about this issue. Without the attention of the provincial government, it does have the potential to become a crisis,” Army Maj. Mike Garcia said. “We will emphasize that we have been pleased with the hard work of both the SOIs and the provincial government and director of police.”

Garcia said he disagreed with Sons of Iraq commanders and some witnesses who said the forces were leaving their posts in droves. “Some may have,” Garcia said, but “there is still a very visible SOI presence throughout Baqouba.”

Meanwhile, in the capital, there was hope that the Sunni political bloc soon might return to the government. The bloc’s six ministers resigned from Prime Minister Nouri al-Maliki’s Cabinet in August, demanding greater political and military clout.

Hassan Hammed Sined, a Shiite member of Parliament who has participated in the negotiations, said, “Most of the conflicts have been resolved. … It’s only a matter of time before (they) return to the government, probably in less than two weeks.”

Salim Abdullah, a spokesman for the Sunni bloc, said significant progress still was needed. “There is no deadline for our return, but we expect within these two weeks, there will be a clear decision,” he said.