A recent Council of Inspectors General on Integrity and Efficiency report accused SIGAR of failing to meet professional standards for investigators and found deficiencies in the audit division.

The reaction following the report was swift on the Hill. At a Congressional hearing Wednesday, members called Fields' work "appalling" and said there is "clearly a lack of competent senior leadership in his agency."

"Fraud, corruption and wasted resources are placing our soldiers and the mission in Afghanistan in danger," said Congressman Tom Coburn, R-Oklahoma, joining Sen. Claire McCaskill, Missouri Democrat, who last week demanded Fields be relieved of his job.

"The president must take swift action and replace the Inspector General and his top staff and immediately appoint an aggressive and independent watchdog who will oversee the billions of dollars the United States is sending there."

The United States has committed $51 billion to Afghanistan reconstruction since 2001, and plans to raise the amount to $71 billion over the next year.

Members of a House subcommittee grilled three US agencies last week for not tracking billions in US money invested in the rebuilding of Afghanistan since 2002.

Additionally, reports that more than $3 billion has been smuggled out of Kabul's airport since 2007 and that Afghanistan ranks as the second-most corrupt country in the world, lawmakers demanded to know where their constituents' money is going.

"Yes, money is leaving Afghanistan," Fields acknowledged, in reference to the Kabul Airport situation.

Agencies including the US Government Accountability Office and US Agency for International Development said there was no question that there was smuggling of money from Kabul Airport, they said that it was unclear whether it was money from the US or not.

The review also showed that Fields' office didn't train investigators in the use of firearms and deadly force, didn't have a policy on firearms and lacked an electronic filing system to collect important information - including data to measure investigators' performance.

Fields, in a letter last week to the review council, said he accepted the report's findings and will work to improve his agency, which the retired Marine major general has led since he was appointed by President George W. Bush in 2008.

Several news stories reported that investigators were reviewing why $5 billion in previously appropriated aid had not been fully spent, how money meant for short-term humanitarian projects was diverted to road building and why Afghan police received inadequate training.

"This report proves that SIGAR's performance is inept," said Sen. McCaskill, chairman of the Senate Homeland Security and Governmental Affairs subcommittee on contracting oversight. "It is time for a housecleaning at SIGAR, including new leadership. For the sake of our soldiers and the American taxpayer, time is of the essence."