A group of U.S. armed extremists occupied the headquarters of a national wildlife refuge in Oregon for a second day Monday in a standoff that they say could last months, to protest against the imprisonment of two Oregon ranchers.

The number of self-styled “militia men” holed up at the Malheur National Wildlife Reserve in northeastern Oregon has not been confirmed. Early estimations believed there to be 150, but reporters who have visited the center claim the number is more like 15.

In Burns, Oregon. pic.twitter.com/frNb7YfZ64

— Ian Kullgren (@IanKullgren) January 3, 2016

The local sheriff's department told reporters the occupation of the headquarters represented an attempt by the “Patriot” gunmen, armed with rifles and clad in military-style uniforms, to provoke a confrontation with authorities.

"These men came to Harney County claiming to be part of militia groups supporting local ranchers, when in reality these men had alternative motives to attempt to overthrow the county and federal government in hopes to spark a movement across the United States," said the statement from David Ward, sheriff of Harney County, where the refuge is located.

The occupation came after several hundred demonstrators marched through Burns, Oregon, to protest against the pending imprisonment of father and son Harney County ranchers Dwight Hammond Jr. and Steven Hammond, who a federal court decided must return to prison after their time served for setting fires on public land to protect their property from wildfires was deemed insufficient.

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According to local newspaper The Oregonian, there were indications that the siege had been planned for “some time.”

The group’s members, who include brothers Ammon and Ryan Bundy, part of the infamous Bundy family who have led anti-federal standoffs in the past, say that they do not seek to stir violence, but will react and even kill if necessary.

Statements from participants of the siege, including the Bundy brothers, reveal that the group’s demands are broad and profound, and call for self-rule in certain zones and call other “Patriots” to arms.

“We’re going to be freeing these lands up, and getting ranchers back to ranching, getting the loggers back to logging, getting the miners back to mining where they could do it under the protection of the people and not be afraid of this tyranny that’s been set upon them,” Ammon Bundy said, in a video posted on Facebook.

U.S. government officials have refrained from calling “the militias” that have occupied a federal property armed with assault rifles domestic terrorists, causing the outrage of many on social media, who on Sunday have said that if the occupiers were Black the scene would be completely different.

“Armed white terrorists have invaded and are currently occupying federal property,” U.S. Uncut reported, while criticizing mainstream media's double standards.

“If you depend on the corporate media for your news, you may not have heard that 150 gun-toting militia are claiming U.S. government property for themselves,” U.S. Uncut added.

#OregonUnderAttack described as family dispute, occupiers, militia men, armed protestors. In fact everything except terrorists. #Oregon

— Calif (@MrKalif) January 4, 2016

"@BernSanders2016: And people say white privilege doesn't exist. Smh #OregonUnderAttack pic.twitter.com/M5AApxfdrH" lmfao

— Ra's El Fab (@PappyGrande_) January 4, 2016