LOS ANGELES (AFP) - An inter-racial couple in Pennsylvania woke up to find the remains of a burnt cross in their front garden. A California town which saw cars and garages vandalised with swastikas, racist epithets and slogans such as "Go Back to Africa." Black effigies hung from nooses in an island community in Maine. Students chanting "assassinate Obama" on a school bus in Idaho. Barack Obama's historic election as America's first black president has led to a surge of racist incidents across the United States, hate-crime monitoring groups and analysts say. Mark Potok, director of the Alabama-based Southern Poverty Law Centre, said the final weeks of the US election campaign and its immediate aftermath had witnessed "hundreds and hundreds" of hate-related incidents. "Since the closing weeks of the campaign, we've seen a real and significant, white backlash break out and I think it's getting worse," Potok told AFP. Potok traced the onset of the incidents to around the time of election rallies by Republican vice-presidential hopeful Sarah Palin where shouts of "Kill Him" were reportedly heard from sections of the crowd. "But what we're seeing now is everything from cross burnings, to death threats, to Obama effigies hanging in nooses to ugly racial incidents in schoolyards around the country," Potok said. "It's been really quite something. I can't quantify the figures beyond saying that clearly there have been hundreds and hundreds of these incidents." Brian Levin, a professor from the Centre for the Study of Hate and Extremism at California State University, San Bernardino also said the rise in hate crimes appeared to fit into part of a longer-term trend. "We don't have exact figures but what I can say anecdotally is that there does seem to be a significant spike in hate crimes from around the election period up until now," Levin said. Levin also said there was evidence of a surge in traffic on white supremacist Internet websites such as StormFront, whose server crashed on the day after the November 4 election due to the uptick in activity.The Southern Poverty Law Centre's chief Potok said the increase in racist crimes could be attributable to a "perfect storm" of conditions. The increase in non-white immigration, the recent estimate by the US Census Bureau that whites would lose their majority status by 2040 and rising unemployment all helped create a climate favourable for hate groups. "Add to all of that the idea of a black man in the White House and you have a very significant number of whites who feel as if they've lost everything, that the country built by their forefathers has somehow been stolen from them," Potok said. "I think we're seeing an identity crisis on the parts of whites." Levin said he had also noticed a ramping up of the vitriol. "It is harder to gauge but it does seem to be much more severe than usual," he said. The racist surge fit into a historical pattern that he described as the "push-me-pull-you" of American politics. "Many times when we've had advancements in race relations in the US we've also had concomitant violent backlashes," he said, citing as an example the fact that the Klu Klux Klan was formed shortly after slavery was abolished in 1865. "Inter-group relations and politics in the US is a marathon and not everyone crosses the finish line at the same time, or at all," he said. For white supremacists, Obama - who has also reportedly named the country's first-ever African-American attorney-general, Eric Holder - represented the doomsday scenario espoused by their ideology, Levin said.