The FBI says it's working with local and state authorities to "bring a peaceful resolution to the situation" at a national wildlife refuge in Oregon.
It's been taken over by armed protesters, who earlier took part in a rally over the prison sentences of two local ranchers.
The standoff is the latest chapter in a long-running dispute between some Westerners and the federal government over the use of public lands.
Dwight and Steven Hammond were convicted of arson three years ago for fires that burned on federal land in 2001 and 2006. They served their original sentences of three months and one year, but an appellate judge ruled in October that the terms were too short under federal minimum sentencing laws. Both men were ordered back to prison for four years each. They have said they plan to turn themselves in today.
Among those occupying the refuge are two sons of Cliven Bundy, who was involved in a standoff with the government last year over grazing rights in Nevada.
Ryan Bundy says he hopes to turn over the land to local authorities so people can use it free of federal oversight. He said he hopes the takeover will prompt others to take action across the country to seize control of federally managed land.
This segment aired on January 4, 2016.