Cliven Bundy, the father of the man who helped start the protest at a federal wildlife refuge in Oregon, was arrested by the FBI late Wednesday night in Portland.
Details of the arrest, including charges and location, were not immediately available. The FBI said those details would be released Thursday morning.
Reached early Thursday at the Bundy ranch house near Bunkerville, Cliven Bundy's daughter Bailey confirmed that Cliven had been arrested but wouldn't provide details. "That's all we know at this time and we're not commenting tonight," she said.
Meanwhile, federal agents closed in on the four remaining militia occupants at the Malheur National Wildlife Refuge near Burns, Oregon, calling for their surrender, the FBI said Wednesday night.
The protesters have been at the refuge since Jan. 2 in a standoff once led by Ammon Bundy, Cliven Bundy's son.
Hours before his arrest, Cliven Bundy's Facebook page posted a message announcing that he was heading to Burns.
The page read: "WAKE UP AMERICA! WAKE UP WE THE PEOPLE! WAKE UP PATRIOTS! WAKE UP MILITA! IT'S TIME!!!!! CLIVEN BUNDY IS HEADING TO THE HARNEY COUNTY RESOURCE CENTER IN BURNS OREGON."
A call to Cliven Bundy's cellphone, shortly after the social media post, went to voicemail Wednesday night, but the box was full.
After hours of negotiations, broadcast live over a YouTube audio feed, the protesters appeared ready to surrender to federal agents at 8 a.m. Thursday. The standoff, which was started by Ammon Bundy and others last month, will enter its 41st day Thursday.
It's unclear whether Cliven Bundy's arrest will affect the protesters' plans to surrender. Cliven Bundy attracted national attention in April 2014 during an armed standoff with law enforcement authorities outside his ranch over his grazing rights on federal land.
In a statement Wednesday evening, the FBI said it moved in on the protesters' encampment at about 4:30 p.m. after one of the occupiers rode an all-terrain vehicle outside the militia-established barricades at the Malheur refuge. FBI agents tried to approach the driver, who sped back to the encampment, the statement said.
"At this time, the FBI has moved to contain the remaining occupiers by placing agents at barricades both immediately ahead of and behind the area where the occupiers are camping. Negotiations between the occupiers and the FBI continue," the statement said.
No shots were fired, the statement added.
The four armed holdouts, David Fry, 27, of Blanchester, Ohio; Sean Anderson, 48, and Sandy Anderson, 47, a married couple from Riggins, Idaho; and Jeff Banta, 46, of Elko, broadcast Wednesday night's events live on an audio feed on YouTube. The Oregonian newspaper said a friend of Fry's used an open phone line to supply the sound.
During the feed, the protesters were heard speaking on the phone to Nevada Assemblywoman Michele Fiore, R-Las Vegas, who flew to Oregon on Wednesday before the events unfolded. Fiore is running for Joe Heck's 3rd Congressional District seat and seemed to be interceding on the protesters' behalf. Christian evangelist Franklin Graham and others had also offered to intervene.
During the live feed, Sean Anderson is heard saying, "We will not fire until fired upon. We haven't broken any laws." At another point, Fry says, "You're going to hell. Kill me. Get it over with."
As Wednesday night progressed, the protesters and Fiore continued talking, apparently with the FBI, about what would happen next; at around 8:30 p.m., the assemblywoman said no resolution seemed likely Wednesday night and asked the protesters whether they had anything to eat. Sandy Anderson repeatedly called for the FBI to "back off."
Ammon and Ryan Bundy started the Oregon protest in support of Oregon ranchers Dwight Hammond Jr. and his son Steven Hammond, who were convicted in 2012 of starting fires on public lands, burning about 140 acres.
Federal prosecutors said the fires were set to hide poaching. The Hammonds, who turned themselves in in January to start five-year federal prison sentences, said the fires were set to protect their property from invasive plants and wildfires.
When the protest started, the Bundys called for the Hammonds to be freed, and for the lands in Harney County, Oregon, to be transferred from the federal government to locals.
Ammon Bundy, Ryan Bundy and nine others were arrested in Oregon on Jan. 26, most of them during a confrontation with the FBI and state police on a roadside. During the confrontation, the militant group's spokesman, Robert "LaVoy" Finicum, was fatally shot. A 12th member of the group turned himself in to police in Arizona.
In a video released by the FBI late last month, Finicum appears to reach into his jacket before police fired their guns. The FBI said Finicum had a loaded 9-millimeter pistol in his pocket.
Two of the arrested protesters have been released on the condition that they wear electronic tracking devices while they await trial. That leaves 10 former protesters, including the two Bundys, in custody.
All 16 protesters have been charged with a single felony count of conspiracy to impede officers of the United States.
"It has never been the FBI's desire to engage these armed occupiers in any way other than through dialogue, and to that end, the FBI has negotiated with patience and restraint in an effort to resolve the situation peacefully," Greg Bretzing, Special Agent in Charge of the FBI in Oregon said in the statement. "However, we reached a point where it became necessary to take action in a way that best ensured the safety of those on the refuge, the law enforcement officers who are on scene, and the people of Harney County who live and work in this area."
In the past several days, the remaining protesters have released a string of caustic videos on the "Defend Your Base" YouTube channel, in which they railed against FBI agents and call them "losers." In one video posted Sunday, Fry said he and Banta face new charges because they added barricades around their encampment; Fry later takes a government vehicle on a joy ride.
In another video posted the same day, Fry says, "The feds, if you're watching this, p--- off, do your jobs, get the hell out of Oregon, get the hell out of all the states."
Las Vegas Review-Journal writer Keith Rogers contributed to this report. Reuters contributed to this story. Contact Colton Lochhead at firstname.lastname@example.org or 702-383-4638. Find him on Twitter: @coltonlochhead. Contact Matthew Crowley at email@example.com Find him on Twitter @copyjockey.Contact Keith Rogers at firstname.lastname@example.org or 702-383-0308. Find him on Twitter: @KeithRogers2