The recession and election of a black president has led to an increased risk from white supremacists, US security chiefs have warned.
An intelligence report by officials at the Department of Homeland Security was issued last week alerting law enforcement agencies to right-wing extremists using the economic downturn to boost recruitment.
Security around Barack Obama has been tight since he was elected as president last year as a result of the perceived risk from racist groups. White supremacist websites received a surge of new members after the election on November 4, analysis has found.
In their latest report, Homeland Security officials said the risk of extremist action had risen as a result of the current circumstances.
The document stated: "Despite similarities to the climate of the 1990s, the treat posed by lone wolves and small terrorist cells is more pronounced than in past years."
It further warns that restrictions on firearms and returning war veterans may lead to terror groups attempting to carry out attacks. Soldiers returning from the Iraq War could appeal to right-wing groups due to their skills and experience, it added.
The assessment came to light after conservative blog sites began to comment on its content.