The Pentagon cannot account for $1.3 billion sent to U.S. commanders Afghanistan as part of an emergency program for critical reconstruction projects, according to an internal report.

The money was sent to force commanders between 2004 and 2014 and accounts for 60 percent of all funds allocated for the program, reported McClatchy.

In an effort to avoid bureaucratic impediment, the money was routed directly to military officers, as it was needed immediately to quickly rebuild destroyed roads, bridges, schools, hospitals, water treatment facilities and other essential infrastructure that were damaged in the more than 13 years of U.S. war in the country, according to McClatchy.

Follow a yearlong investigation, U.S. inspector general for Afghanistan John F. Sopko found that the Pentagon either couldn't, or refused to, provide basic financial information regarding the whereabouts of 6 in 10 dollars of the $2.26 billion spent as part of the Commander's Emergency Response Program over the past decade.

"In reviewing this data, SIGAR found that the Department of Defense could only provide financial information relating to the disbursement of funds for CERP projects totaling $890 million (40 percent) of the approximately $2.2 billion in obligated funds at that time," the report says.

Sopko and his staff divided the expenditures into the 20 categories set for the emergency program, such as transportation, education, health care, agriculture, water and sanitation. By far the biggest category was a 21st, coined "unknown," which had 5,163 projects, while 4,494 projects were placed in the 20 defined categories.

The Pentagon refused to comment on Sopko's findings, although U.S. Central Command, which oversees military operations in Afghanistan and 19 other countries, said that some of the money was likely redirected from reconstruction efforts to more direct needs, like counterinsurgency, according to McClatchy.

But McClatchy noted that counterinsurgency isn't one of the 20 categories defined by the Pentagon regulations for the emergency program, and it's not clear why money earmarked for reconstruction would need to be used to pay for counterinsurgency operations that are already paid for by the Pentagon.

It's far from the first time the U.S. military has misplaced millions of taxpayer dollars.

Sopko released a different report in April noting that the Pentagon is unable to track $45 billion in Afghanistan reconstruction funds due to a flawed accounting system.

In 2014, The Washington Times reported that the Pentagon admitted to losing track of 40 percent of the firearms it provided to Afghanistan's security forces.

Following the U.S.-led Iraqi invasion in 2003, the U.S. spent $25 billion to train and arm Iraqi security forces. The Pentagon admitted in 2007 that it lost track of about 190,000 Ak-47 assault rifles and pistols given to those Iraqi forces between 2004 and 2005, reported The Washington Post. Many of those Iraqi forces were eventually defeated by the Islamic State group in 2014, who confiscated U.S.-supplied weapons, notes RT.

And officials admitted in March that they lost more than $500 million in U.S. military equipment given to Yemen, including guns, ammunition, helicopters, Humvees, night-vision goggles, and patrol boats.