Ammon Bundy was arrested at a traffic stop, but the source provided no additional details.
A law enforcement source told CNN that shots were fired during the traffic stop, though it was not clear who opened fire first.
A source with the Pacific Patriots Network, a self-styled militia group that has supported the occupation, said the Federal Bureau of Investigation informed its members that Bundy was arrested and that two people were shot during the traffic stop.
(Reporting by Curtis Skinner in San Francisco; Editing by Lisa Shumaker)