US authorities have arrested two white supremacists for threatening to kill Democrat Barack Obama during a "killing spree" of African-Americans, court records showed.

The two men planned to kill 88 people and decapitate 14 African-Americans, before assassinating Senator Obama while dressed in tuxedos and top hats, the documents revealed.

Daniel Cowart and Paul Schlesselman were arrested last Wednesday (US time) in Tennessee for possession of firearms and threats against a candidate running for president, the documents from the Memphis court showed.

The men discussed a "killing spree to include targeting a predominantly African-American school ... they further stated that their final act of violence would be to attempt to assassinate presidential candidate Barack Obama," Brian Weaks, an agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives told the court.

Cowart, from Bells, Tennessee, and Schlesselman, from Arkansas, met via the internet a month ago and have "very strong beliefs and views regarding 'White Power' and 'Skinhead' views," Mr Weaks said in his statement to the court.

Cowart had bought one rifle and stockpiled two handguns, both stolen from his grandfather.

They planned to steal another high-powered rifle from a gun store in Jackson, Tennessee, as well as a series of robberies to finance their bloody actions.

"Schlesselman stated that they planned to drive their vehicles as fast as they could toward Senator Obama shooting at him from the windows," Mr Weaks said.

"Both individuals stated they would dress in all white tuxedos and wear top hats during the assassination attempt. Both individuals further stated they knew they would and were willing to die during this attempt."

There has been no immediate comment on the incident from Barack Obama's campaign.

Senator Obama, who has made history by becoming the first black presidential nominee of a major political party, is already under secret service protection having received it much earlier in the campaign than any other candidate.

In late August, the alarm was also raised when it was revealed three men were arrested with a weapons cache in Denver, Colorado where the party convention was being held.

US attorneys later said there had been no credible threat against Obama.

-AFP/ABC