Armed protesters continue to occupy a building at a national wildlife refuge in a remote part of Oregon as they argue that a father  and son who are headed back to prison for arson on federal lands are being sent there unfairly.

Why are they doing it and what do they hope to gain? Here are a few things to know about the standoff.

What was the spark?

A father and son in Burns, Oregon, were convicted three years ago of burning federal land in Oregon. Dwight Hammond, 73, served three months in prison  on the conviction, and his son, Steven, 46, served one year. In October, however, a federal judge ruled the pair had served too little time under a federal anti-terrorism law that requires a mandatory minimum sentence of 5 years for fires that damage public property but cause no injury or death. The two were ordered back to prison to serve four years each. They are to report Monday morning.

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Why did they burn the land?

The Hammonds claimed they burned the land to reduce the growth of invasive plants and to protect their land, which borders federal property, from wildfires. Prosecutors say the fire set in 2001 which burned  139 acres of Bureau of Land Management lands, was set to cover-up illegal deer hunting.

Who is protesting?

Around 300 people rallied in Burns, Oregon, Saturday in protest of the adjusted sentences for the Hammonds whose property is nearby. Saturday afternoon, a group  from the protests took over the wildlife refuge. The leader of the standoff  is Ammon Bundy. Bundy is the son of Cliven Bundy who had his own run-in with federal authorities over grazing rights on federal lands. Ammon Bundy, along with a group of men described as militiamen from several other states, were the ones who occupied the Malheur National Wildlife Refuge nearly 300 miles southeast of Portland on Saturday. They are armed. Bundy claims there are 100 men there. That number has not been confirmed.

Bundy issued this statement via his Facebook page Saturday.

Do the Hammonds want the help?

"Neither Ammon Bundy nor anyone within his group/organization speak for the Hammond Family," the Hammonds' lawyer W. Alan Schroeder wrote to local law enforcement authorities this weekend. According to The Associated Press, Dwight Hammond has said he and his son plan to peacefully report to prison Monday as ordered by the judge. "We gave our word that's what we would do, and we intend to act on it," he told The AP last week.

What is the Malheur National Wildlife Refuge?

The refuge, according to a National Parks website, is  a federal wildlife preserve where, "People and wildlife have been drawn to the resources of this oasis of wetlands in the high desert of Oregon for thousands of years. With over 320 bird species, Malheur is a mecca for birdwatchers." The refuge is located  half an hour south from Burns near Malheur Lake. 

The refuge is closed “until further notice,” and has posted this explanation on its website:

“The Fish and Wildlife Service is aware that an unknown number of armed individuals have broken into and occupied the Malheur National Wildlife Refuge facility near Burns, Oregon. While the situation is ongoing, the main concern is employee safety and we can confirm that no federal staff were in the building at the time of the initial incident. We will continue to monitor the situation for additional developments.”