The owners of a Montana gold mine sent a letter to the U.S. Forest Service earlier this month warning its employees to stay off the owners’ property.

“Anyone entering onto the White Hope Mine, without previous coordination, will be charged” and arrested under Montana code, the letter read, according to court documents.

“At no time will weapons be allowed onto the White Hope Mining Claim,” the letter concluded.

Except there are weapons on the White Hope Mining Claim, in the hands of armed militia members the mine owners recruited to protect their claim. And the feds aren’t letting the aggression stand.

U.S. Attorney Michael Cotter filed a civil suit Tuesday in federal court in Helena, Montana against George Kornec and Phil Nappo, owners of the White Hope Mine near Lincoln, Montana. The suit alleged the miners opened a road, built a garage and cut down trees on their mining claim without authorization, stored another individual’s explosives on the site, and illegally turned members of the public away from the land by locking the gates to the property shut and posting no-trespassing signs.

“The unauthorized and illegal actions of Defendants have interfered with and damaged National Forest Service land,” the complaint stated. “Because the non-compliance has not been resolved, and because members of the public are still being threatened or blocked from access, it is necessary for the United States to bring this action.”

The suit also noted that defendants and the Oath Keepers, a loose-knit national organization of current and former U.S. military and law enforcement officers that pledge to uphold the Constitution, were “acting in concert or joint participation, in interfering with public and Forest Service access on public lands, including the White Hope unpatented mining claims.”

In a press release issued Saturday, the Oath Keepers of Josephine County and the Idaho Three Percenters, another militia group, said they were recruited by Kornec and Nappo following “threats” to their mining venture. They referred to their activity at the White Hope Mine as “Operation Big Sky.”

“We are committed to securing the mine site of George Kornec and Phil Nappo, owners of Intermountain Mining LLC, which was requested due to threats to their mining venture,” the press release read. “There is a dispute between the actions taken by the United States Forest Service and the miners. Our goal has been and will continue to be to secure that area from threats until a legal action takes place within the court system.”

It’s unclear what the “threats” to Kornec’s and Nappo’s mining claim were. Court documents showed that the U.S. Forest Service sent a non-compliance notice to the pair in August 2014 that forbid any mining activity until the outstanding issues were resolved. The agency also ordered the unauthorized garage to be removed by June 30.

The Oath Keepers of Josephine County are the same activists who earlier this year backed a pair of Southwestern Oregon gold miners in their dispute with the Federal Bureau of Land Management. A spokeswoman for the group, Mary Emerick, told TPM back in May that the group planned to take action to help other local property owners with land management disputes following a stand-down at the Sugar Pine Mine in Galice, Oregon. She declined to elaborate on those plans.

But the group has regathered in recent days at the White Hope Mine, more than 800 miles away from Josephine County. Lewis & Clark Couty Sheriff Leo Dutton told local TV station KRTV that the Oath Keepers’ presence in Lincoln had the potential to unsettle local residents.

“We did talk about them when they initially showed up, of being in camouflage and (carrying) weapons — not that Lincoln is immune to seeing people in camouflage and weapons,” Dutton told KTVR. “Just a bunch of people they didn’t know, showing up in camouflage and weapons, they were unfamiliar with — it does cause them concern.”

The Oath Keepers also made national headlines this week when they reappeared in Ferguson, Missouri during a night of protests marking the one-year anniversary of the police shooting of 18-year-old Michael Brown. The armed men told media outlets that they were there protecting a journalist for conspiracy theorist extraordinaire Alex Jones’ website, Infowars.com; Infowars later said that the militia members came to Ferguson at the behest of local business owners and offered a reporter their protection.

Read the complaint below:

