White extremist groups, including the Ku Klux Klan, is emerging from decades of obscurity, with hundreds of hate-related incidents reported since the election of Obamna to the White House.

Though the FBI is still in the process of compiling hate-crime statistics for 2008, those based on local media reports have forced experts to describe the surge as unprecedented. Some officials compared it to the rise in attacks on Muslims after the 9/11 attacks.

"The rhetoric right now is just about out of control," said Brian Levin, Director of Center for the Study of Hate and Extremism at California State university, San Bernardino.

"When you get this depth of hatred, it usually is the smoke before the fire," he was quoted as saying by the ‘Los Angeles Times’ newspaper.

The FBI is investigating whether the recent Klan-related incidents involve conspiracies. And the Secret Service is monitoring the racist activity "to try to stay ahead of any emerging threats to Obama," according to spokesman Darrin Blackford.

Noose hangings, racist graffiti and death threats have struck dozens of towns across the United States. More than 200 such incidents -- including cross burnings, assassination betting pools and effigies of Obama -- have been reported, according to law enforcement authorities and the Southern Poverty Law Center, which monitors hate groups.

"We've seen everything from cross burnings on lawns of interracial couples to effigies of Obama hanging from nooses to unpleasant exchanges in schoolyards," said Mark Potok, Director of the Intelligence Project at the Southern Poverty Law Center, based in Montgomery, Alabama.

Potok said there have also been numerous incidents in schools of racial tension and name-calling connected to the election, particularly in Southern states.

"I think we're in a worrying situation right now, a perfect storm of conditions coming together that could easily favor the continued growth of these groups," Potok was quoted as saying by the influential US daily.

"The hysterical tone of many of the media pundits and the harsh qualities of rhetoric pushed by some policy-makers at a local level have created a toxic environment which is promoting violence against immigrants and immigrant communities," said Karen Narasaki of the Asian American Justice Centre.

One white supremacist leader, describing himself as moderate, professes alarm. "There is a tremendous backlash to Obama's election,” said Richard Barrett, the leader of the Nationalist Movement in Learned, Mississippi.

"My focus is to try to keep it peaceful. But many people look at the flag of the Republic of New Africa that will be hoisted over the White House as an act of war," he stressed.

In the highest-profile case, a federal grand jury indicted Jeffrey Conroy, 17, for second-degree murder and classed it as a hate crime last week after Marcelo Luce's of Ecuadorean descent was stabbed to death on New York's Long Island.

The attack has been seen in the context of a steady rise since 2003 in violence against Latinos, the largest immigrant group in the United States.