UPDATE, 7 pm: Just before 4:30 this afternoon, FBI agents and Oregon State Police arrested Ammon Bundy, ringleader of the weeks-long standoff at a Harney County wildlife refuge, along with his brother and three others. A shootout ensued during the arrest, according to a terse press release from the FBI, killing one person and injuring another.

Occupiers arrested in that incident, reportedly during a traffic stop:

Ammon Edward Bundy, age 40, of Emmett, Idaho
Ryan C. Bundy, age 43, of Bunkerville, Nevada
Brian Cavalier, age 44, of Bunkerville, Nevada
Shawna Cox, age 59, Kanab, Utah
Ryan Waylen Payne, age 32, of Anaconda, Montana

State Police also arrested another man, 45-year-old Joseph Donald O'Shaughnessy, in Burns. Authorities aren't saying which of the arrestees was injured in the shootout, or who died.

This doesn't necessarily mean anything, but JJ MacNab, a reporter who's been closely covering the standoff, notes a consistent face of the occupation—Arizona rancher LaVoy Finicum—wasn't mentioned in the FBI's release.

All six arrestees face a federal felony for "conspiracy to impede officers of the United States from discharging their official duties through the use of force, intimidation, or threats."

You can find the full release here.

Update: The Oregonian confirmed with Finicum's daughter that the 55-year-old was the occupier killed this afternoon.

Two other people with ties to the occupation, self-styled journalist Pete Santilli and militant Jon Ritzheimer, are in custody. Santilli was arrested in Burns. Ritzheimer in Peoria, Arizona, where he was visiting family. Both men face the same felony charge as other arrestees.

Original post:

Shortly before 6 pm, rumors began circulating on Twitter that Ammon Bundy, ringleader of the Harney County occupation, had been arrested by federal agents, and that shots have been fired. The source for the information initially was Pete Santilli, a self-described "journalist" and militant sympathizer who's been live-streaming feeds from the occupation. But other factors—the lockdown of a Burns hospital and a state highway, suggest something has indeed occurred to shake up the standoff that's gripped Oregon for the last three weeks.

Harney County Sheriff Dave Ward is expected to release more information.

Bundy and occupiers were reportedly headed to a meeting in John Day. Apparently that's not happening:

On a livefeed, Santilli's been phoning people affiliated with the standoff to report Bundy and others are in custody, but he's also quoting headlines from Fox News. He doesn't seem to know much about what's happened. KATU has reported four people are in custody.

Update, 6:29 pm: CNN is reporting that Bundy is, in fact, in custody:

As background, the standoff started on January 2, when armed militants protesting what they've called federal overreach took over unoccupied buildings at the Malheur National Wildlife Refuge near Burns. The size of Bundy's clan has seemed to swell in the intervening three weeks (there are reports children are now at the compound) but the demands have been largely the same. The group has said it would turn over the refuge over to ranchers, miners, and loggers. They've also called on local ranchers to refuse to pay the feds to graze on public lands.

The occupation began after anti-government militants began traveling to Eastern Oregon to attempt to keep two Harney County ranchers, Dwight and Stephen Hammond, from having to serve out years-long federal prison sentences. The men turned themselves in days after the standoff began.