The number of hate groups operating in the United States has increased by 54 percent since 2000 -- growth fueled in part by anger over immigration, a failing economy and the election of President Obama.

Those are among the findings of the latest "Year in Hate" issue of the Southern Poverty Law Center's Intelligence Report, which identified 926 hate groups active in 2008. That's an increase of more than 4 percent from the 888 groups in 2007 and far more than the 602 groups documented in 2000.

"That's a record for us," said SPLC's Mark Potok in a webcast about the report held today. "It's a real and significant rise."

The number of hate groups by state roughly tracks population, says Potok. That's why California -- the most populous state -- also has the greatest number of SPLC-documented hate groups, with 84. Those groups tend to be concentrated in the southern part of the state, where anger over undocumented immigrants is particularly fierce.

The U.S. South is also home to a large number of hate groups. After California, Texas has the second-highest concentration of such groups with 66, followed by Florida with 56, South Carolina with 45, Georgia and New Jersey tied for third place with 40 each, Tennessee with 38, Pennsylvania with 37, Alabama with 36, North Carolina and Missouri with 30 each, and Virginia with 26.

Among the latest trends documented in the SPLC report is a growth in the extreme-right "sovereign citizens" movement infamous for filing bogus property liens and other so-called "paper terrorism" tactics. The report also cites increasing militancy by the extremist fringe of the Hebrew Israelite movement, whose followers believe Jews are evil and that all whites deserve death or slavery.

Other hate groups that have been particularly active include:

* Ku Klux Klan organizations, which in 2008 increased from 155 chapters to 186;

* Neo-Nazi  groups, which held book burnings, swastika lightings and a music festival; and

* Racist skinheads, whose Confederate Hammerskins organization held a St. Patrick's Day concert in Florida that attracted attendees from across the country.

SPLC is also concerned about calls for extremist violence against President Obama. During the webcast, Potok mentioned the two white-supremacist plots to assassinate him, including the one involving two skinheads arrested in Tennessee who also planned to murder black students.

Potok also discussed the more recent case of Kody Brittingham, a 20-year-old Marine from Camp Lejeune, N.C. arrested for his alleged involvement in an armed robbery. During the investigation into that crime, police found a journal he had been keeping that detailed an elaborate plot to assassinate the president. A federal grand jury recently returned an indictment against Brittingham for making threats against Obama.

The SPLC report notes that last September's cover of National Socialist magazine depicted the then-presidential nominee in the crosshairs of a scope with the headline "Kill This Nigger?"

"Barack Obama's election has inflamed racist extremists who see it as another sign that their country is under siege by non-whites," said Potok.