Armed occupiers at an Oregon wildlife refuge have driven heavy equipment on or near sensitive tribal lands, and rifled through native artifacts, federal and tribal officials told BuzzFeed News.

Without inspecting the 187,000-acre wildlife refuge, it was unclear to know what sites, including camping and burial sites sacred to the Paiute Tribe, had been disturbed. Yet officials said aerial photographs showed militia members who took over the Malheur National Wildlife Refuge earlier this month had plowed new roads and driven heavy equipment near sensitive sites.

"They're driving with impunity, and just flat out not giving a crap where they drive, dig, scoop or build," Jason Holm, a spokesman for the U.S. Fish and Wildlife Service told BuzzFeed News. "There's an immense threat to items in places that are irreplaceable to the culture."

Armed protesters, many of them members of militia groups, took over the refuge Jan. 2 after attending a protest against the incarceration of two local ranchers. The group has protested the management of land by the federal government and have asked for federal lands be turned over to local ranchers.

In the 19 days of their occupation, the group has also torn down fences and used gravel at the refuge to pave roads.

Charlotte Rodrique, chairperson of the Burns Paiute Tribal Council told BuzzFeed News she had seen aerial photos of the area that showed occupiers had also paved new roads at the refuge, possibly driving over areas that are important to the tribe and protected by federal law.

"They have broken the law, and we've been assured they are going to be investigated," Rodrique said.

In a video posted Thursday, some of the occupiers were also seen going through artifacts that are kept by the U.S. Fish and Wildlife Service at the refuge. One of the leaders, LaVoy Finicum, is heard criticizing federal officials for how the artifacts are kept, saying there were signs of a rat infestation.