This the moment captured on video when a raging militant brandishing an assault rifle taunts law enforcement officers, telling them: "You want some militiamen? Come get some."

The video comes amid mounting tensions as the FBI surrounds the group's Oregon encampment at the Malheur National Wildlife Refuge, a day after member and Arizona rancher LeVoy Finicum was shot dead in a confrontation with police during a traffic stop nearby.

Leader Ammon Bundy, his brother Ryan, who was shot in the arm, and three others travelling in the same convoy as Finicum were arrested. The FBI said that three others were also arrested separately in connection with the occupation.

Authorities have now set up roadblocks all along the perimeter of the wildlife compound that the militia had seized almost a month ago on 2 January. The roadblocks are manned by police and FBI agents reportedly armed with assault rifles and wearing body armour and helmets.

"The media's been ordered to leave. That means they're coming to kill us and they don't want them to see that. They're going to murder all of us," says the unidentified militiaman wearing military fatigues, his face just inches from the camera lens.

"Damn, show the truth, show the truth!" yells the gunman. He appears to be on patrol with another man in a balaclava as a large earth-moving machine is being operated in the background.

"The media's been waiting for a bloodbath the whole time we've been here. Now there's going to be one and they're running," he shouts. "American people better wake up, get here and fight for your country right now!" He also encourages members of the military to fight for their country "right here." if "anyone tries to stop you, kill them," he urges.

His partner adds: "What ya gonna do when the militia comes after you, FBI?"

The militia wants federal pastures lands, currently rented by ranchers, to be turned over to the private property owners. The new apparent leader of the group, Jason Patrick, said the militia will remain at the wildlife refuge until there is a "redress of grievances" from the federal government. He earlier told the media to "prepare for the peaceful resolution" of the standoff, the Oregonian reported.

But Finicum had vowed on an earlier video before his death: "We're not leaving, we're staying. These buildings do not ever return to the federal government." He also told the press: "I would rather die than be caged."

A militia member and witness to Finicum's shooting said that Finicum had fled a police roadblock in his truck. When it careened into a snowbank, he exited and charged at law enforcement and was shot, the witness reported, according to Vice. But another account on the Bundy Ranch Facebook page said that Finicum exited his truck with his hands raised.

At a local news conference the FBI special agent in charge of the agency's Portland office, Greg Bretzing, said that the remaining occupiers were "free to leave" the refuge and would be identified at law enforcement checkpoints. "Let me be clear: It is the actions and choices of the armed occupiers of the refuge that have lead us to where we are today," Bretzing said.

Neither the FBI nor local police provided details of Finicum's death. But Harney County Sheriff Dave Ward said he was "disappointed that a traffic stop yesterday that was supposed to bring peaceful resolution to this ended badly. Multiple law enforcement agencies put a lot of work into putting together the best tactical plan they could, to take these guys down peacefully.

"This has been tearing our community apart. It's time for everybody in this illegal occupation to move on. There doesn't have to be bloodshed in our community."

Those arrested face federal felony charges of conspiracy to use force, intimidation or threats to impede federal officers from discharging their duties, the FBI said.

A statement from LaVoy Finicum posted to Youtube the day he was shot to death in a confrontation with law enforcement.DefendYourBase on YouTube