The last four militia members remaining in the armed takeover of a federal building in an Oregon wildlife refuge have released new videos mocking the FBI and calling for "good American people" to rise up and "get rid of scumbags."

They call the FBI agents "idiots" and "losers," and show off the barricades they have constructed against government forces. One defiantly drives around in a federal vehicle, defying officials to levy more charges against him.

FBI agents, in an effort to avoid further bloodshed, continue to negotiate with the four more than a month after militia members stormed the federal building on the Malheur Wildlife Refuge. The militia is protesting federal control of federal pasture lands and want the government to give away the real estate to ranchers.

Member LaVoy Finicum was shot dead by federal agents during a confrontation off the refuge in late January and most of the remaining militants were either arrested or surrendered then or soon after.

In one of the latest videos militiaman David Fry claims opponents have desecrated a memorial to Finicum. "That's the kind of people we're dealing with now, absolute trash, scumbags," he says. "These people kill babies, for crying out loud, in their mother's womb.

"That's the people we're fighting against," Fry adds. He calls on "all the good people in America" to "get rid of" the scumbags.

Leader Ammon Bundy was arrested the night Finicum was killed. But his father, Cliven, is calling for the occupation to continue. Cliven Bundy had his own showdown with federal law enforcement in 2014 when they arrived on his Nevada ranch to confiscate his cattle in lieu of more than $1m (£700,000) he owed the government for rental on federal pasture lands. Bundy faced down the feds with armed supporters and didn't give up his cattle, nor pay his rent.

He's now on his way to Burns, Oregon, where his sons Ammon and Ryan are in custody, and plans to join a demonstration on their behalf. He's urging Western ranchers to tear up the grazing contracts they signed with the federal government.

The militia members have said their only remaining link to the outside world is a mobile phone provided by the FBI. Yet they're still able to upload videos to their Defend Your Base YouTube channel.