PORTLAND, Ore. — A group of armed activists who have seized control of part of a federal wildlife refuge in southern Oregon appear to be aiming “to overthrow the county and federal government,” a local law enforcement official said Sunday.

Harney County Sheriff David M. Ward said authorities from “several organizations” are working to peacefully resolve the standoff, which began Saturday when an unknown number of armed activists occupied an uninhabited building at the Malheur National Wildlife Refuge, about 30 miles outside the town of Burns, Ore.

“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,” Ward said in a statement Sunday.

There were no signs of confrontation Sunday at the small refuge headquarters building, seized in what activists said was a protest against the federal prosecution of two ranchers and a bid to reclaim local control of federally managed land.

“We ask that people stay away from the refuge for their safety,” Ward said.

“At this time, we do not have any information that any other areas in Harney County are in immediate danger,” he said.

County officials announced that schools would remain closed through the week pending a resolution.

U.S. Sen. Ron Wyden, D-Ore., said the FBI was leading the law enforcement response, in coordination with the Oregon State Police and local law enforcement authorities. Wyden said he was himself heading to southern Oregon to meet with local residents.

“I understand why rural Oregonians are so frustrated about this economy,” Wyden said a news conference. “But the next step from frustration is not to walk off a cliff, misled by some outsiders who seem willing to take the law into their own hands.”

Those leading what amounts to an armed occupation at the remote building say they are the vanguard of a national movement to resist the government’s ownership of vast stretches of land in the West.

The move began Saturday after a peaceful rally near Burns, where more than 150 people gathered in support of the ranchers who are facing additional jail time for arson.

Dwight Hammond, 73, and his son Steven Hammond, 46, said they set fires in 2001 and 2006 to reduce the growth of invasive plants and protect their Harney County property from wildfires.

The two were convicted of the arsons three years ago and served time –Dwight three months, and Steven a year. But a judge ruled their terms were too short under federal law and ordered them back to prison for about four years each.

Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.