FBI officials say they arrested the leader of the armed militia occupying the Malheur wildlife refuge and several others, and one person was killed during a shootout with federal agents

An associate of the armed Oregon militia occupying a wildlife refuge was shot dead on Tuesday after a shootout with federal agents that resulted in the arrest of the group’s leader Ammon Bundy and a group of protesters.

The shootout appears to have taken place on a highway in rural Oregon – away from the federal refuge the armed militia have been occupying.

FBI officials said they arrested Bundy, his brother Ryan Bundy, Bryan Cavalier, Shawna Cox and Ryan Payne on Tuesday afternoon after they stopped them along the highway.

The agency described the shootout and arrests as resulting from “an enforcement action to bring into custody a number of individuals associated with the armed occupation of the Malheur National Wildlife Refuge” that occurred at 4.25pm PST.

It is was not clear how many rounds were exchanged during the incident.

The man who died was identified by his daughter as Robert “LaVoy” Finicum, one of the main spokesmen for the group. Police did not confirm his identity, but said the person killed was “a subject of a federal probable cause arrest”. One individual suffered non-life-threatening injuries and was transported to a local hospital for treatment, the FBI said in its statement. He was arrested and is currently in custody.

Reached by phone Tuesday night, Cliven Bundy, Ammon’s father, who led a standoff with the federal government in 2014, said he was devastated by the reports. “My sons are good people and they were there to help … It’s a rotten shame that people there are not trying to harm anybody and now they are shooting them dead.”

He added: “We’re not going to put up with this … This is a pretty big deal for America. This is the way they treat people who try to help? We are tired of the abuse.”

Members of the militia had planned to attend a community meeting in the town of John Day, which is north of the Malheur national wildlife refuge that militiamen have been occupying since 2 January.

Facebook Twitter Pinterest Ammon Bundy and other protesters were arrested. Photograph: Rick Bowmer/AP

In a separate incident, Joe Oshaughnessy – another rightwing activist who earlier claimed he was trying to prevent violence from erupting at the refuge – was arrested in Burns, the closest town to the wildlife refuge.

At 6.30pm PST, FBI officials also arrested Pete Santilli, a conservative Ohio radio host who has been a vocal supporter of the Bundys and was earlier live-streaming the chaos outside of a hospital in Burns.

Santilli, Oshaughnessy and the men arrested on the highway are all facing federal felony charges of conspiracy to impede officers through the use of force, intimidation or threats.

Jon Ritzheimer, another prominent occupation leader who often helped run the militia’s “security” team, was also arrested late Tuesday night. Officials say Ritzheimer turned himself in at a police department in Peoria, Arizona, and that he was arrested without incident. He is also facing a federal felony charge.

Harney County judge Steve Grasty, who has for weeks demanded that Bundy and the militia end the protests, said he was saddened to hear that there has been a death. “I’m deeply disappointed … that it looks like there has been a fatality,” he told the Guardian by phone. “This is so hard on everybody – our community and even the occupiers.”

Grasty said he couldn’t say yet whether the standoff was over. “I don’t know that it’s over. I have no idea what is happening at the refuge.” He added: “I’m glad to see this winding down, but we wanted this to come to a peaceful end and it didn’t.”

Bundy and a group of rightwing protesters stormed the refuge to protest the federal government and the imprisonment of two ranchers in rural Harney County.