Militia members claimed that roughly 100 supporters took control of the Refuge's headquarters, according to The Oregonian. However, a woman told Oregon Public Broadcasting she only saw 15 people while delivering food to the militiamen.

Ammon Bundy, son of Nevada rancher Cliven Bundy, and two of his brothers helped occupy the building Saturday night. They said they were not looking to hurt anyone, but in a phone interview Ryan Bundy told The Oregonian protesters were willing to kill or be killed, if necessary.

 Protesters told The Oregonian at issue are the rights of states, counties and individuals to manage local lands. The occupation was prompted by the prosecution of Dwight Hammond Jr. and Steven Hammond, who lit fires to reduce the growth of invasive plants that spread to federal land in 2001 and 2006. They were convicted of arson three years ago and served time but a judge ruled their terms were too short and ordered them back to prison.

The Hammonds are supposed to return to prison Monday.

"We're planning on staying here for years," Ammon Bundy told The Oregonian. "This is not a decision we've made at the last minute."

Bundy called for other "patriots" to join the group in a video posted to Facebook.

In a statement released to The Oregonian Saturday night, Harney County Sheriff Dave Ward confirmed multiple agencies were working to investigate and diffuse the situation at the Malheur National Wildlife Refuge. He asked bystanders to stay clear of the scene.

This is not the first time the Bundys have confronted federal authority.

In 2014, after the Bureau of Land Management sought to remove Bundy's cattle from public rangeland, armed militiamen confronted federal officials. Bundy stopped paying grazing fees over 20 years ago and owes more than $1 million.