Washingtonians are becoming increasingly unnerved by the sudden presence of unmarked militias who have been deployed to the streets of the US capital as protests rage, but who won’t identify themselves to citizens and journalists.

Videos and photographs of the mysterious and heavily-armed figures have been swirling on social media for days, with many who have encountered them reporting that they refuse to say which government agency they are working for.

The anonymity of the forces has led some to suggest they look like armed “mercenaries” rather than government employees. One DC-dweller tweeted that the nation’s capital felt like it was “under some sort of military occupation.”

Completely unmarked officers in riot gear holding protesters blocks away from the White House. No badges. No insignias. No name tags. Nothing. Refused to tell us who they’re with. #DCprotest#DCprotestspic.twitter.com/c4lFFCsX48— Ben Davis (@bdaviskc) June 4, 2020

One ominous-looking video posted on Thursday shows lines of burly men without any identifying ID tags or insignias standing guard near the White House. “Refused to tell us who they’re with,” the tweeter who posted the video said.

Some of the men identified themselves only as being with “the Department of Justice,” according to one Mother Jones journalist.

It turns out that at least some of the men are prison riot officers sent in by the Federal Bureau of Prisons at the request of Attorney General William Barr, according to NBC. A statement from the bureau said the officers are un-badged because they are “serving a broader mission.”

Though that doesn’t seem like an entirely legitimate excuse for the lack of identifying information. Demonstrators protesting police brutality are concerned that if any of the badgeless officers seriously injure anyone or commit other crimes while patrolling the capital, that there will be no way to identify them.

5PM WHITE HOUSE — These are the unidentified DOJ officers holding the perimeter at 15th and H Streets.They won’t tell the public to whom they report exactly…It’s generating HUGE frustration here #GeorgeFloyd@WUSA9pic.twitter.com/GOSbeyplLb— Mike Valerio (@MikevWUSA) June 3, 2020

It appears DC is not the only place where the unmarked police have shown up. Some people tweeted about similarly unidentified forces at Philadelphia protests, too.

“How is anyone supposed to know for sure he’s even a real cop?” one person wrote in response to a photo of an armed man clad head-to-toe in black at one Philly protest.

tell me why this pointy nose bitch and all the other cops can take their badge numbers and other identifying information off and that’s ok but protesting them is not #phillyprotestpic.twitter.com/4PeibMj95d— cindy vortex 🥺 ACAB (@anactualfairy) May 30, 2020