PRINCETON, Ore. (Reuters) - The leaders of a group of self-styled militiamen who took over a remote U.S. wildlife refuge center in Oregon over the weekend said on Monday they acted to protest the federal government’s role in managing millions of acres of wild lands.

The anti-government occupation, which began on Saturday at the Malheur National Wildlife Refuge, 30 miles (50 km) south of the small town of Burns, was the latest skirmish over federal land management in large tracts of the West.

A protest leader, Ammon Bundy, told reporters outside the occupied facility on Monday that his group had named itself “Citizens for Constitutional Freedom” and was trying to restore individual rights. Bundy and law enforcement officials declined to say how many people were occupying the center.

About half a dozen occupiers could be seen outside the facility on Monday, with some manning a watchtower and others standing around a vehicle they had used to block the road leading to the building. They chatted quietly among themselves. None was visibly armed.

The FBI said it was seeking a “peaceful resolution to the situation.” It declined to give details on how the U.S. government would deal with the occupiers. No significant law enforcement presence could be seen at the site.

The occupation followed a demonstration in Burns over the imminent imprisonment of local ranchers Dwight Hammond Jr. and his son, Steven Hammond, who were found guilty of setting a series of fires. Through an attorney, they have dissociated themselves from the occupiers.

NBC News reported that the father and son turned themselves in as planned on Monday at a federal prison in California. Their lawyer did not immediately respond to requests for comment.

The occupation is the latest wrinkle in decades of conflict between ranchers and the federal government over Washington’s management of hundreds of thousands of acres of range land. Critics say the federal government often oversteps its authority and exercises arbitrary power without sufficient accountability.

Bundy is the son of Nevada rancher Cliven Bundy, whose ranch was the scene of an armed demonstration against federal Bureau of Land Management (BLM) officials in 2014 that ended with the authorities backing down, citing safety concerns.

That standoff had drawn hundreds of armed protesters after federal agents sought to seize Bundy’s cattle because he refused to pay grazing fees.

Jon Ritzheimer, a Marine Corps veteran who traveled from Phoenix to take part in the occupation, said the Constitution was under attack from the U.S. government, and that he and his companions were “trying to restore this land to the people.”

In Burns, home to 3,000 people, residents voiced sympathy for the Hammonds but also expressed frustration at the occupation, which some locals viewed as the work of outsiders.

“I agree they shouldn’t have to go back to prison. I get why they’re here,” said Patrick Wright, a 33-year-old taxi driver, who said he knew the Hammonds. “Taking over the refuge and threatening gun violence is a little extreme, but it’s getting them heard, that’s for sure.”

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The takeover drew criticism on social media, with some users asking if the occupiers would have been treated differently if they had been black or Muslim.

SERIES OF FIRES

The Hammonds were found guilty in 2012 of setting a string of fires, including a 2001 blaze that federal prosecutors said was intended to cover up evidence of deer poaching, that wound up burning 139 acres (56 hectares) of public lands.

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The younger Hammond was initially sentenced to 12 months in prison and the father three months, below the federal minimum for arson. But in October, a U.S. district judge increased the sentences to five years.

The Hammond ranch borders on the southern edge of the Malheur refuge, a bird sanctuary in eastern Oregon’s arid high desert, about 305 miles (490 km) southeast of Portland.

Both father and son are members of the Oregon Cattlemen’s Association (OCA). The group said on Monday that it would continue to assist and represent them “solely through avenues that are in accordance with the law.”

“OCA does not support illegal activity taken against the government. This includes militia takeover of government property, such as the Malheur Wildlife Refuge,” the association’s president, John O’Keeffe, said in a statement.

“Obviously we’re aware of the situation and concerned about it,” said White House spokesman Josh Earnest. He said President Barack Obama had been briefed on the situation, adding: “This ultimately is a ... local law enforcement matter.”

Republican White House candidates Senator Ted Cruz of Texas and Senator Marco Rubio of Florida expressed sympathy for the protesters’ concerns but urged the group to remain peaceful and follow the law, according to media reports.

The refuge, which encompasses 292 square miles (75,630 hectares), was established in 1908 by U.S. President Theodore Roosevelt as a breeding ground for greater sandhill cranes and other native birds.