WASHINGTON (AP) — Domestic extremist groups pose a serious threat to the military by seeking to recruit service members into their ranks and, in some cases, joining the military to acquire combat experience, according to a Pentagon report released Tuesday.

The report, prepared last year at the request of Congress, did not assess whether the problem of extremism in the military is growing, but it cited a number of examples of service members with extremist affiliations. It said the number of current and former military members who ascribe to white supremacist ideology is unknown.

“Military members are highly prized by these groups as they bring legitimacy to their causes and enhance their ability to carry out attacks,” the report said. “In addition to potential violence, white supremacy and white nationalism pose a threat to the good order and discipline within the military.”

For example, the report noted that a Marine was discharged in 2018 for having ties to a neo-Nazi group called Atomwaffen Division, and it said the group’s co-founder served in the Army National Guard in Florida.

Another Marine was determined to be the founder of a different white supremacist group, called AIM, which stands for American Identity Movement. The group spread propaganda through an operation it called “Project Siege” and as of March 2019 had about 500 members. The group’s founder was a former Marine sergeant and a former leader was an Army veteran. Several other members of the military and the Reserves were identified as being associated with the group, and the report noted that some were either demoted or discharged.

The report described a social media post, reported by a service member, who claimed to “see plenty of our kind” in combat arms. The message recommended ways to identify fellow group members, saying “simply wear a shirt with some obscure fascist logo.”

The military has long been aware of small numbers of white supremacists and other extremists in its ranks, but the problem burst into public awareness after the Jan. 6 insurrection at the U.S. Capitol, where an outsized number of military veterans and some current military members were present. It quickly fell to a new Pentagon chief, Lloyd Austin, to determine the scale of the problem and try to fix it.

On Feb. 5, Austin directed all commanders and supervisors at every level of the military to conduct a one-day “stand down” — a pause in normal business — by early April to discuss extremism in the ranks.

At his first Pentagon news conference two weeks later, Austin said extremism is a threat to the bonds of trust between service members, who count on cohesion to make them effective on the battlefield.

“I really and truly believe that 99.9 percent of our service men and women believe in” the oath they swear when entering the military, Austin said, adding that the actual number of extremists in the military is unknown.

“I expect for the numbers to be small, but quite frankly, they’ll probably be a little bit larger than most of us would guess,” he said. “But I would just say that, you know, small numbers in this case can have an outsized impact.”

Austin often mentions that he has personally witnessed the damage that racism and extremism can inflict. In 1995, when then-Lt. Col. Austin was serving with the 82nd Airborne Division at Fort Bragg, North Carolina, three white soldiers described as self-styled skinheads were arrested in the murder of a Black couple who were walking down the street. Investigators concluded the two were targeted because of their race. The killing triggered an internal investigation, and all told, 22 soldiers were linked to skinhead and other similar groups or found to hold extremist views.