When planners devised the Baghdad security plan late last year, they had assumed most Baghdad neighborhoods would be under control around July, according to a senior American military officer, so the emphasis could shift into restoring services and rebuilding the neighborhoods as the summer progressed.

“We were way too optimistic,” said the officer, adding that September is now the goal for establishing basic security in most neighborhoods, the same month that Bush administration officials have said they plan to review the progress of the plan.

Lt. Gen. Raymond T. Odierno, the senior American ground commander in Iraq, said in a brief interview that he never believed that a midsummer timetable for establishing security in Baghdad was realistic. “This was always going to be conditions-driven,” he said, noting that he always had expected it would take until fall to establish security across much of the city.

But in order to meet that timetable, he added, the Iraqi Security Forces would have to make strides in coming months at maintaining security. “Ultimately the I.S.F., and specifically the police, are the key to holding an area,” he said. “We have to within the next four months move them more toward holding the areas we have cleared.”

The last of the five combat brigades ordered to Iraq as reinforcements as part of the security plan will increase the number of American troops in the city to around 30,000, up from 21,000 before the operation, an American officer said.

In addition, around 30,000 Iraqi Army and national police forces and another 21,000 policemen have been deployed in Baghdad. Many of the Iraqi units have turned up at less than full strength and other units have been redeployed from the capital, General Brooks said, leaving fewer than expected.

Image Neighborhoods like Ameel, Baya, Jihad and Furat remain violent.

American commanders have also had to send troops outside the capital, to deal with a sharp rise in violence in Diyala Province and to search for American soldiers kidnapped south of the capital.