The arrest was the first made since the group took over buildings at the Malheur National Wildlife Refuge on Jan. 2 in the latest conflict over the U.S. government's control of land in the West.

Law enforcement officials had so far kept their distance from the site, located about 30 miles (48 km) south of the small town of Burns in Oregon's rural southeast, in an effort to avoid a violent confrontation.

But police arrested Kenneth Medenbach, a 62-year-old resident of Crescent, Oregon, after he drove a vehicle owned by the U.S. Fish and Wildlife Service to a local supermarket on Friday, the Harney County Sheriff's office said in a statement.

He was charged with unauthorized use of a motor vehicle. Medenbach could not be reached for immediate comment and it was unclear if he had retained an attorney.