WASHINGTON — Defense Secretary Jim Mattis blasted the Pentagon bureaucracy for “cavalier” spending in light of a recent report that showed as much as $28 million had been wasted in buying uniforms for the Afghan army, according to a memo obtained by USA TODAY.

The report found that U.S. military officials have purchased the forest-camouflage uniforms since 2007 without testing their effectiveness, or accounting for the fact that just 2% of Afghanistan is covered by woods. The Special Inspector General for Afghanistan Reconstruction also found that special tailoring boosted the cost of the uniforms, as did using a licensed camouflage pattern when free versions were at hand. The report will be the focus of a hearing by a panel of House Armed Services Committee on Tuesday.

“Cavalier or casually acquiescent decisions to spend taxpayer dollars in an ineffective and wasteful manner are not to recur,” Mattis wrote.

Mattis’ letter is unusual in that the military regularly pushes back at reports by the special inspector general’s office, which is led by John Sopko. It has disputed his finding, for example, that millions were wasted building a gas station in Afghanistan.