The Southern Poverty Law Center based its findings on online chatter among extreme right-wing groups.
Cliven Bundy's faceoff with the Bureau of Land Management agents and Las Vegas police at his ranch in southern Nevada in April has "invigorated" an extremist movement that has exploded since President Barack Obama was elected, growing from 150 groups in 2008 to more than 1,000 last year, the Southern Poverty Law Center said.
The report warns of the potential for more violence like the recent killing of two Las Vegas police officers by a pair of anti-government zealots — Jerad and Amanda Miller — who spent time at Bundy's ranch before they were asked to leave because of their extremist views.
"Cliven Bundy may have faded from public view, but the movement that spawned him is boiling," said the report entitled "War in the West, The Bundy Ranch Standoff and the American Radical Right."
"Government officials need to understand what motivates this movement because the Millers will not be the last to demonstrate their anti-government rage," it said.
The BLM says Bundy owes over $1 million in fees and penalties for trespassing on federal property without a permit for more than 20 years. Bundy, whose ancestors settled in the area in the late 1800s, refuses to acknowledge federal authority on public lands.
The bureau backed down during the showdown with Bundy and his armed supporters, citing safety concerns, and released some 380 Bundy cattle collected during a weeklong operation from a vast arid range half the size of Delaware.
Among other things, the report praised U.S. Attorney General Eric Holder's recent revival of the Domestic Terrorism Executive Committee established in the aftermath of the 1995 Oklahoma City bombing.
It calls for the criminal prosecution of those who pointed weapons at law officers at the Bunkerville ranch and urges Congress to spend more money to combat the threat of non-Islamic domestic terrorism.
Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.