PORTLAND, Ore. (Reuters) - Jury selection began on Wednesday in the case of ranchers Ammon and Ryan Bundy and five other anti-government activists who led an armed 41-day takeover of a federal wildlife refuge in Oregon, the U.S. Attorney's Office said.

The seven defendants are charged with conspiracy to impede federal officers and possession of firearms in a federal facility during the standoff at the Malheur National Wildlife Refuge, about 300 miles (483 km) southeast of Portland.

Once a jury is seated, opening arguments are expected to begin next week in the federal courthouse in Portland.

The takeover of the wildlife refuge was the latest flare-up in a decades-old conflict over federal control of millions of acres of public land in the West. The Bundy brothers have been at the forefront of that movement and stood by their father, Cliven Bundy, at his Nevada ranch in a 2014 armed standoff with authorities over enforcement of federal grazing rights.

The Bundys began the Oregon standoff on Jan. 2 with at least a dozen armed men, sparked in part by the return to prison of two Oregon ranchers who set fires that spread to federal property near the refuge.

More than two dozen people have been charged in connection with the takeover. Federal prosecutors dropped charges against one of the Bundys' co-defendants, Peter Santilli, who livestreamed events at the refuge, writing in a motion filed on Tuesday that "the interests of justice do not support further pursuit of these charges."

Another of the occupiers, Corey Lequieu, the first of the 26 people on trial, was sentenced to 2-1/2 years in federal prison earlier this month, local media reported.

A second group of defendants are scheduled to go on trial in February.

The Bundys have been jailed since they and several others were arrested in January on a snow-covered road near the reserve. A spokesman for the group, Robert "LaVoy" Finicum, was shot and killed by Oregon State Police who thought he was reaching for a weapon.

(Reporting by Courtney Sherwood in Portland, Oregon, and Alex Dobuzinskis in Los Angeles,; Writing and additional reporting by Eric M. Johnson in Seattle; Editing by Bill Trott)