The U.S. has spent $732 million since 2002 to more than double Afghanistan's energy capacity, but 85 percent of urban households remain without electricity, a watchdog said in a report released Saturday.

Retired Marine Gen. Arnold Fields, the special inspector general for Afghanistan reconstruction, said in the report that results have been "disappointing" and that current projects face delays and rising costs because of deteriorating security and poor oversight by U.S. agencies.

The report also said the Afghan government lacks a clear plan for how to continue developing its energy sector, and that it is unable to collect enough utility fees from users to maintain the infrastructure that has been built so far.

Afghanistan's energy capacity has multiplied from 430 megawatts in 2001 to 1,029 in September, the report said. Still, Afghans continue to suffer severe shortages, forcing most people to rely on costly generators or go without power.

Only about 15 percent of urban households had access to electricity compared with only 6 percent of households in rural areas, the report said, citing figures from Afghan Energy Information Center.

The reconstruction effort has come under increased scrutiny as President Barack Obama has shifted the U.S. focus from Iraq. The office headed by Fields was established by Congress in 2008, nearly seven years after the U.S. invasion to oust the Taliban.

The topic is expected to be on the agenda at a Jan. 28 international conference on Afghanistan in London.

Saturday's report said only one of six projects this year had been completed on time. Most were delayed by three to six months because of poor contractor performance, poor contract oversight or security concerns.

The report cites corruption — including bribes given to meter readers in exchange for falsifying records to indicate that less power was used — for the Afghan government's failure to collect enough revenue to keep the power grid running.

"This has resulted in the need for the United States and other donors to spend millions on such expenses to ensure the operations and maintenance of its projects," the report said.

Fields also found that the Afghan government has little direction for developing the energy sector.

"It is troubling that we have been participating in the reconstruction of Afghanistan for eight years and there is no updated energy sector master plan against which the U.S. and the international community can contribute and measure success," Fields said in a statement accompanying the report.