The Pentagon reportedly overcharged the armed forces about $6 billion for fuel, using the windfall for its other projects in a practice officials defended as perfectly legal, according to a report The Washington Post.

The Washington Post obtained documents showing the Defense Department was excessively charging the armed forces up to $1 additional per gallon or more, compared to what commercial airlines would pay for market rate jet fuel. Since 2010, the Pentagon has reaped a surplus worth billions by slapping a premium on fuel sales.

According to the publication, the overage was used to fund expenses, including $450 million towards a prescription drug program for troops and families that was rife with fraud. In addition, around $80 million was diverted for training Syrian rebels, and $1.4 billion used to offset the additional costs of the war in Afghanistan. The controversial prescription drug plan was reportedly on the hook for $1.7 billion worth of fraudulent insurance claims, The Post said, citing defense auditors.

However, the Pentagon told the publication the higher charges were legal, noting Congress approved the tactic as a clear way to balance the Defense Department's books. Still, the department has has been under scrutiny for irresponsible budgeting practices, after an internal study showed the Pentagon was wasting $125 billion in administrative costs, the Post added.

The full story can be found at The Washington Post.