The Air Force has the biggest racial disparities among their military justice practices out of all the US military branches, according to the previous report from the organization Protect our Defenders, which published the findings on the topic four years ago.

Black airmen with between six and 10 months of experience were twice as likely to be disciplined by superiors or face court martial as white airmen in 2016.

But the organization's newest report says the military branch did not adequately address the issue.

"Despite the Air Force's internal findings in 2016 that it has a 'consistent' and 'persistent' racial disparity in prosecutions of Black servicemembers, it appears the Air Force has done nothing in the last four years to solve the problem," Protect our Defenders president Don Christensen said in a statement Wednesday.

"Instead, the Air Force dedicated time and effort to cover up its failure to act on any solutions," said Christensen, a former Air Force chief prosecutor who obtained new documents about the matter through the courts.

They show that a task force to tackle the problem was formed in 2016 but that it came up with only vague recommendations that were never formally presented to military leadership.

Air Force spokeswoman Ann Stefanek acknowledged the racial disparities in the military justice system.

"While we have taken steps to elevate unconscious bias training at all levels of our command structure, we have more work to do to identify and remove barriers that stand in the way of our people's success," she said in a statement to AFP.

The original 2016 Protect our Defenders report sparked a congressional investigation that then called on the Air Force to correct the inequalities.