Seven other people, including Mr. Bundy’s brother Ryan Bundy, were arrested, the authorities said. Another person was hospitalized with injuries that were not life-threatening.

The authorities did not identify the man who was killed, but a member of the Nevada State Assembly, Michele Fiore, who has been a supporter of the Bundy family, said on Twitter that it was LaVoy Finicum. Mr. Finicum had become a de facto spokesman for the occupiers.

The confrontation came after more than three weeks of growing tension and anxiety that put the tiny community of Burns — about a five-hour drive from Portland — into an international debate about homegrown right-wing militias, public lands and constitutional rights. Mr. Bundy, 40, and a group of his followers, adopting the name Citizens for Constitutional Freedom, occupied the Malheur National Wildlife Refuge, about 30 miles southeast of Burns, in Harney County, on Jan. 2.

Community leaders demanded that the group leave, but several members were still occupying the refuge Tuesday night.