Image copyright Reuters Image caption Agents had kept their distance from the reserve until now

The four armed occupiers of a US government wildlife reserve in the US state of Oregon are preparing to surrender, a member of the group says.

Sean Anderson said they would leave the Malheur complex on Thursday morning, in a live broadcast on the internet.

Earlier, the FBI moved in on the group, which had been entrenched for 40 days.

They are protesting against federal government control of local land. One activist died in an earlier confrontation with police.

Agents were placed behind barricades near the self-styled militia's encampment, an FBI statement said.

Inside the Oregon refuge with the militiamen

A 'militiaman apart'

The group's discussions with the FBI, which were broadcast over the internet, at times became hysterical.

One occupier, David Fry, yelled at an FBI negotiator saying: "You're going to hell. Kill me. Get it over with."

He also said: "We're innocent people camping at a public facility, and you're going to murder us."

Putting down weapons

Image copyright Reuters Image caption Events escalated on Wednesday after one of the four drove a vehicle outside barricades erected by the group

All four of the militia - a husband and wife and two other men - were said to be present during a discussion, broadcast live online, about how they would put down their weapons and walk out of the refuge at 08:00 local time (16:00 GMT).

They will meet a Nevada lawmaker, Michele Fiore, and a preacher who are travelling to meet them. Ms Fiore, a Republican member of the Nevada state assembly, was also on the live conference call.

While the deadline has passed, Ms Fiore was reported to be still en route to the refuge where the occupiers remain. Mr Anderson says that they still plan to surrender.

Image copyright Getty Images Image caption Robert "LaVoy" Finicum was shot and killed by FBI agents when they tried to detain him at a traffic stop - his funeral took place on 5 February

'Remember Braveheart?' By James Cook, BBC News

The live stream of events inside the refuge has been a strange mixture of prayer and paranoia, of fear and defiance.

The occupiers have repeatedly accused the federal government of persecuting them and they have attacked President Barack Obama for trying to "take away guns from people who are depressed".

With tens of thousands listening, the militia revealed that they had been eating well, talking about hearty cooked breakfasts, pork fried rice and steaks.

At one point, an occupier compared himself to the Scottish patriot William Wallace, suggesting that he too would rather die than give up his freedom.

"Remember Braveheart? Braveheart took it to the end even when he was tortured," he said.

At other times members of the quartet have sounded despairing, repeatedly expressing the fear that they will be shot dead.

As well as Mr Anderson, 48, the other occupiers have been named as Sandy Anderson, 47; David Fry, 27; Jeff Banta, 46.

The four had refused to leave despite the arrest of the group's leader Ammon Bundy last month. He has urged those remaining to stand down.

On Wednesday night Ammon's father, Cliven Bundy, was arrested by the FBI at Portland International Airport.

Local media reported that he faces federal charges in relation to a 2014 confrontation at his ranch. The stand-off between federal agents and Mr Bundy's supporters was the culmination of a two-decade dispute over grazing rights on federal land.

The Malheur National Wildlife Refuge was seized early in January. The armed takeover was sparked by the return to prison of two Oregon ranchers accused of burning federal land.

It developed into a wider protest demanding the return of government-controlled land to locals.

Mr Bundy and others were arrested late in January in a confrontation with police that left one of the activists, LaVoy Finicum, dead.

The FBI said its agents moved in on the four on Wednesday after one of them drove a vehicle outside barricades erected by the group.

"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," the statement said.

The Oregon stand-off

Image copyright AFP

How did it begin?

In October, a federal judge ruled the sentences on two Oregon ranchers, Dwight and Steven Hammond, for burning federal land were too short and jailed them for about four years each.

Angered by the ruling, Nevada native Ammon Bundy began a social media campaign backing them and travelled to Burns, Oregon, organising meetings.

His group attracted supporters from across a number of states and Mr Bundy called it Citizens for Constitutional Freedom. On 2 January the armed militiamen took over the Malheur National Wildlife Refuge - and widened the range of demands.

What are the militia's aims?

It is an extension of the Sagebrush Revolution of the 1970s and 1980s that demanded the transfer of federal land in many western states to local control.

Mr Bundy's own father - a Nevada rancher - had been involved in a protest over cattle-grazing rights in 2014. One policy is to try to persuade ranchers to tear up their federal grazing contracts.

Although many local residents are sympathetic with its cause, many also oppose the occupation of the refuge. Even the local ranchers who are serving the longer sentences distanced themselves from the militia.

Are militias legal?

The term has a complex history and generally refers to those outside the official military who can be called on in times of need. The US Constitution refers to the president having command of "militia of several states" and that Congress "can call forth militia" to tackle insurrection and invasion.

Those who form such militias cite the constitution and various references in federal and state law as granting them legality.