By Callie Carmichael, CNN
(CNN) - The number of American "patriot" extremist groups has reached a record level, according to a new study, and experts are warning of a wave of anti-government violence.
A report released Tuesday by the Southern Poverty Law Center counted 1,360 "patriot" extremist groups in 2012 - up by 7% from 2011. The study defines patriot groups as anti-government militias driven by their fear that authorities will strip them of their guns and liberties.
"They believe the Constitution is being raped. With hate groups, things are going to get worse because they feel like they're in battle," said David Gletty a former FBI informant who spent time undercover with various militia and extremist groups. "It's not surprising with their hatred of President (Barack) Obama that there are even more hate groups out there."
The study said California has the most patriot extremist groups, with 81.
The SPLC report also offers a bit of good news: The number of "immigrant-bashing" extremist groups - so-called nativism organizations - is way down from 2011, falling by 88%.