The FBI has surrounded the four remaining protesters occupying the Malheur National Wildlife Refuge in Oregon, local media reported.

According to the Oregonian, the FBI has placed armored vehicles around the area where the occupiers are located.

The FBI has encircled the four remaining occupiers at the Oregon wildlife refuge. Agents in armored vehicles are demanding they surrender. — Les Zaitz (@LesZaitz) February 11, 2016

“At this time, the FBI has moved to contain the remaining occupiers by placing agents at barricades both immediately in front of and behind the area where the occupiers are camping."

"Negotiations between the occupiers and the FBI continue. No shots have been fired,” the FBI said in the statement.

The FBI stated that the situation began when one of the remaining protesters had ridden an ATV beyond the barricades set up by the occupiers. The individual was spotted by the FBI, but as agents tried to approach the driver, he turned around and sped back to the refuge.

Further updates will be released as appropriate. https://t.co/P7Q2LSeyca#OregonStandoff — FBI Portland (@FBIPortland) February 11, 2016

Those remaining at the refuge have been identified as David Fry, Jeff Banta, and Sean and Sandy Anderson, who are husband and wife.

The move by the FBI came on the 40th day of the Malheur occupation. It began when a group of armed ranchers and protesters took over the refuge headquarters to protest federal land management and express their anger over the arson convictions of two other ranchers under an anti-terror law.

In an audio live-stream of the standoff posted by activist Gavin Seim on YouTube, the occupiers debated how to proceed. The protesters invoked the Constitution numerous times and held prayers, while worrying over the possibility of the situation coming to a violent end.

READ MORE: Oregon grand jury indicts 16 wildlife refuge occupiers – prosecutors

“They killed LaVoy!” a protester said multiple times, referring to rancher LaVoy Finicum, who was fatally shot during a roadside confrontation between law enforcement and the occupiers.

That confrontation also led to the arrest of multiple protesters, including leader Ammon Bundy.