Washington (CNN) -- Four U.S. senators are calling on President Barack Obama to fire the man watching over tens of billions of dollars allocated for reconstruction of Afghanistan.
The one Democrat and three Republicans say in a letter to the president that they want Arnold Fields dismissed as special inspector general for Afghanistan reconstruction, or SIGAR.
"It has been clear for several months that SIGAR's mission is not being served effectively. ... SIGAR would be better served with new leadership," the letter states.
The letter is signed by Claire McCaskill, D-Missouri, Tom Coburn, R-Oklahoma, Susan Collins, R-Maine, and Charles Grassley, R-Iowa. It indicates the senators had written twice previously about concerns regarding the agency.
"We urge you to act now," the letter says. "We are disappointed by your administration's ongoing failure to take decisive action to make changes at SIGAR."
A spokeswoman for the inspector general's office said Fields had been on a plane to Afghanistan Thursday and was not immediately available for comment.
The senators' demand for Fields' ouster comes amidst growing concerns about corruption in Afghanistan and the inability of the United States to keep track of how the billions of dollars it has invested in reconstruction are spent.
U.S. taxpayers spent more than $51 billion on Afghanistan reconstruction between 2002 and 2010, with much of that going to training Afghanistan security forces. Obama's recent budget requests asked for an additional $20 billion, according to the inspector general's website.
An earlier audit of the office by inspectors general from other federal agencies found it fell short of some professional standards. Fields himself requested that audit, which was unusual for such a young agency. It was formed in 2008.
"We observed deficiencies and significant noncompliance with these standards," said that report from the Council of Inspectors General on Integrity and Efficiency.
The senators said the report found numerous problems with the office's work.
"The reviews also found that the agency has no meaningful strategic plan for their audits and investigations and that leadership at SIGAR remains more concerned with the quantity of their work rather than the quality," the senators said in their letter.
In a letter for Secretary of State Hillary Clinton and Defense Secretary Robert Gates, Fields says he accepted all the recommendations in the report, calling them "invaluable in helping us operate more efficiently and effectively."
He said in that August 6 letter, posted on the office's website, that many changes had been made already and that he expected all to be addressed by the end of this month.
Spokeswoman Susan Phalen reiterated that the special inspector general had welcomed the review and had taken steps to implement its suggestions.
"As the SIGAR informed the Senate in a letter dated August 6, 2010, substantially all of the CIGIE recommendations will have been addressed by September 30, 2010," Phalen said in an e-mail to CNN.
"Specifically, SIGAR has taken immediate action to address the concerns regarding its investigations directorate, and is in full compliance with all the attorney general's guidelines for inspectors general with statutory law enforcement authority," she said.