The top government watchdog for Afghanistan reconstruction testified Tuesday that a criminal investigation has been opened into the controversial purchase of forest camouflage-patterned uniforms for Afghan National Army soldiers.

The U.S. military has been accused of wasting millions on the dark green "relish" uniforms that stand out in the desert setting. Only 2 percent of Afghanistan is covered by forests.

“These problems are serious,” Special Inspector General John Sopko told the House Armed Services Committee. “They are so serious that we started a criminal investigation related to the procurement of the ANA uniforms.”

Sopko said he also wants a review of all organizational clothing and individual equipment contracts made by the Combined Security Transition Command-Afghanistan (CSTC-A), which is responsible for the bulk of the training, advising and assisting of Afghan security forces.

Sopko said CSTC-A bought more than 1 million uniforms with a proprietary pattern without testing its effectiveness between 2007-2015.

The purchase came with a $93 million pricetag – of which up to $28 million could have been shaved off.

“This $93 million procurement demonstrates what happens when people in the government don’t follow the rules,” Sopko told the panel.

He highlighted 10 specific areas of concern with the CSTC-A, including that it only showed the Afghan minister of defense proprietary camouflage patterns owned by one company – Canadian manufacturer HyperStealth Biotechnology Corp.

“CSTC-A failed to consider other available camouflage patterns including those owned by the Department of Defense which would have been cheaper perhaps and equally effective,” Sopko said, faulting CSTC-A for not testing the effectiveness of the pattern.

At the time, the Afghan minister of defense reportedly liked the “woodland, urban and temperate patterns” which came at an additional cost of $28 million.

Sopko also called out U.S. commanders for buying uniforms that came with pricier features like zippers instead of buttons and 88,000 extra pairs of pants.

In a memo obtained by Fox News on Monday, Defense Secretary Jim Mattis cited Sopko’s report and criticized the Pentagon for its “cavalier” spending on uniforms for the Afghan National Army.

Mattis highlighted the overspending in a July 21 memo to the Defense Department’s acquisition, policy and finance chiefs. He called the purchase an “example of a complacent mode of thinking” and cautioned the department that the missteps are “not to recur.”

He added that “buying uniforms for our Afghan partners, and doing so in a way that may have wasted tens of millions of taxpayer dollars over a ten-year period, must not be seen as inconsequential in the grand scheme of the department's responsibilities and budget.”

The U.S. has been involved in the Afghanistan war for almost 16 years. Nearly $110 billion has been appropriated in Washington for reconstruction in Afghanistan.

Fox News' Lucas Tomlinson contributed to this report.