U.S. Defense Secretary Jim Mattis has criticized Pentagon officials for wasting as much as $28 million by making a questionable choice of forest camouflage-patterned uniforms for Afghan National Army soldiers.

The uniform pattern was selected without evaluating its effectiveness when only 2.1 percent of Afghanistan is covered by forests, the U.S. government’s top watchdog on Afghanistan said in a report last month.

The Afghan minister of defense at the time “liked the woodland, urban and temperate patterns,” the report by the Special Inspector General for Afghanistan Reconstruction (SIGAR) said.

It potentially cost up to an additional $28 million dollars between 2008 and 2017, the watchdog said.