Bundy ranch
An anti-government protester with an assault rifle defending Cliven Bundy's ranch in 2014Reuters

As many as 150 far-right armed militiamen seized control of a building belonging to the federal government in the US state of Oregon last night. Local media has reported the group has seized the main office of the Malheur National Wildlife Refuge and its visitor center and aims to take over a US Bureau of Land Management fire station.

The group has vowed "we will do whatever it takes to maintain our freedom", and issued a call on Facebook for others to join them at Malheur National Wildlife Refuge, a remote lodge roughly 50 miles away from the small city of Burns in central Oregon.

Ammon Bundy, the son of Cliven Bundy, a Nevada rancher involved in a fierce armed stand-off with the American government in 2014, appears to be leading the occupation. He posted a video on Facebook saying: "This is not a time to stand down. It's a time to stand up and come to Harney County", where Burns is located.

The group had planned to use the building as a sanctuary for two Oregonian ranchers – father and son Dwight and Steven Hammond – who were convicted of arson for setting fire to government land next to their own, and are due to report to prison on Monday. The Hammonds, communicating through their lawyers, have distanced themselves from the protest, and say they will arrive at prison as ordered.

The group, which is mostly made up of agitators from outside the state, grabbed the building shortly after a peaceful rally of about 300 people in defence of the Hammonds, and claim to be hunkered down for the long haul.

Ammon Bundy and his brother Ryan Bundy told Oregon Live that "they are not looking to hurt anyone, but that they would not rule out violence if police tried to remove them".

Ammon Bundy said: "The facility has been the tool to do all the tyranny that has been placed upon the Hammonds.

"We're planning on staying here for years, absolutely," he added. "This is not a decision we've made at the last minute."

Domestic terrorists or libertarians?

The group is an offshoot of the Sovereign Citizen movement, a right-wing conspiracy theory which believes that the US government is too powerful. They want to turn over Oregon's federally owned land over to local miners and loggers.

Bundy also said that his group was willing to die to defend what they believe are constitutionally protected rights for states and citizens to use local lands.

He told Oregon Live: "The best possible outcome is that the ranchers that have been kicked out of the area, then they will come back and reclaim their land, and the wildlife refuge will be shut down forever and the federal government will relinquish such control. What we're doing is not rebellious. What we're doing is in accordance with the Constitution, which is the supreme law of the land."

In a statement, Harney County Sheriff Dave Ward said: "A collective effort from multiple agencies is currently working on a solution. For the time being please stay away from that area. More information will be provided as it becomes available. Please maintain a peaceful and united front and allow us to work through this situation."

BREAKING! SHARE! Standing for the rights of Men & Women. Calling all freedom loving people to come to Harney County...

Posted by Bundy Ranch on Saturday, 2 January 2016