NEW YORK Because of unforeseen security costs, haphazard planning and shifting priorities, the U.S.-financed reconstruction program in Iraq will not complete scores of projects that were promised to help rebuild the country, according to a U.S. oversight agency.

Only 49 of the 136 projects that were originally pledged to improve Iraqi water and sanitation will be finished, along with about 300 of an initial 425 projects to provide electricity, according to the report released Thursday.

The planners of the rebuilding effort did not take into account hundreds of millions of dollars in administrative [corruption] costs, and mostly did not realize that the United States would have to spend money to keep things like power plants and sewage treatment plants running once they had been built, the report says. That ultimately reduced the money available for rebuilding projects.

Reconstruction officials and some specialists outside the government have said that the full extent of the Iraqi insurgency and lawlessness would have been difficult or impossible to anticipate when much of the planning for the rebuilding effort took place under the Coalition Provisional Authority in 2003.

The report says that the authority planners "envisioned a much more permissive security environment," but does not take a stand on whether the possibility of such problems should have been considered.