The White House announced Monday that retired Maj. Gen. Arnold Fields, the special inspector general for Afghanistan reconstruction whom lawmakers in both parties have criticized for being ineffective, has resigned.

“For more than 40 years, General Fields has been committed to securing our national defense. As he moves on to new challenges, he can do so confident in the knowledge that the president and the American people owe him a debt of gratitude for his courage, leadership, and selfless service to our nation,” the White House said in a statement.

The White House praised Fields, who took the post in 2008, for organizing a staff of more than 120 people that has since “produced numerous critical reports that have improved reconstruction efforts, and helped insure that U.S.-funded programs are achieving their objectives.”

But several senior lawmakers, including strong allies of President Barack Obama, have accused Fields of failing to adequately monitor the allocation of billions of reconstruction dollars invested in Afghanistan and have been calling for his resignation.

Sens. Claire McCaskill (D-Mo.), Tom Coburn (R-Okla.) and Susan Collins (R-Maine) sent a letter to Obama in December 2009 to express “serious concerns” about Fields’ ability to recruit competent staff members and his shop’s overall lack of auditing.

“We request that you conduct a thorough review of SIGAR, including its staff, operations and execution of its mission, in order to determine if improvements can be made to the organization,” they wrote. “We urge you to take all necessary remedial actions to ensure effective oversight of reconstruction activities in Afghanistan.”

Rep. Mike Honda (D-Calif.) blasted Fields in a column headlined “The Afghan Money Pit,” which was published last month in the Los Angeles Times. Honda criticized Fields for producing only four convictions to date and for conducting investigations that have failed to meet minimum standards, even though “billion-dollar projects granted in Washington end up in Afghanistan with a mere fraction of funds left.”

“Skimming and bribery are pervasive,” Honda wrote. “Congress created the post … to provide independent and objective oversight of the war’s stabilization and reconstruction funds, but like so much about the war effort, there isn’t enough to show for it.”