Over the weekend, Ammon Bundy, the son of Cliven Bundy, the Nevada rancher, and his armed supporters, broke off from a peaceful rally in Burns, Oregon, and stormed the headquarters of the Malheur National Wildlife Refuge in support of two ranchers  convicted of committing arson on public lands.

“We will be here as long as it takes,” he said in an interview posted on the Bundy Ranch’s Facebook page.

NBC reported Monday the FBI was leading efforts to bring a “peaceful” end to a armed standoff.

Here is a look at what’s behind the protest:

— As my colleague Marina Koren reported Sunday, Bundy maintains that Malheur National Wildlife Refuge, which is managed by the U.S. Fish and Wildlife Service, is, in his words, “owned by the people, and it has been provided to us to be able to come together and unite to make a hard stand against [government] overreach.”

— Bundy and the others are ostensibly there in support of Dwight Hammond, 73, and his son Steven Hammond, 43. The Hammonds were convicted in 2012 of committing arson on public lands in 2001. They had claimed they set fire to the lands, which they leased from the government for grazing cattle, to fight off invasive species.

As Marina reported:

When the Hammonds were originally sentenced, they argued that the ​minimum mandatory sentence for arson on federal land—five years—was unconstitutional ... The trial court agreed and reduced the sentence. But an appeals court eventually upheld the federal law, and a judge imposed the mandatory sentence last October, with credit for time the Hammonds already served.

Dwight Hammond had served three months in prison, while Steven Hammond had served a year. They are expected Monday to report to prison. Their attorney maintains Bundy and the protesters do not speak for the Hammonds.

—Bundy and his brother Ryan, who is also taking part in the standoff, are the sons of Cliven Bundy, the Nevada rancher who staged his own standoff against agents from the federal  Bureau of Land Management in 2014. The elder Bundy, while excoriating the local sheriff and government, told Oregon Public Broadcasting that he wasn’t sure what his sons and their supporters can achieve.

“I don’t quite understand how much they’re going to accomplish,” he said. “I think of it this way: what business does the Bundy family have in Harney County, Oregon?”

OPB has extensive coverage of this story, and you can follow their reporting here.