WASHINGTON - U.S. authorities say federal agents have broken up a plot to assassinate Democratic presidential candidate Barack Obama and shoot or decapitate 102 black people in Tennessee.

In court records unsealed Monday, federal agents said they disrupted plans to rob a gun store and target a predominantly African-American high school by two neo-Nazi skinheads. Agents said the skinheads did not identify the school by name.

Jim Cavanaugh, special agent in charge of the Nashville field office for the Bureau of Alcohol, Tobacco, Firearms and Explosives, said the two men planned to shoot 88 black people and decapitate another 14. The numbers 88 and 14 are symbolic in the white supremacist community.

The men also sought to go on a national killing rampage, with Obama as its final target, Cavanaugh told The Associated Press.

"They said that would be their last, final act - that they would attempt to kill Senator Obama," Cavanaugh said. "They didn't believe they would be able to do it, but that they would get killed trying."

An Obama spokeswoman travelling with the senator in Pennsylvania had no immediate comment.

The men, Daniel Cowart, 20, of Bells, Tenn., and Paul Schlesselman 18, of West Helena, Ark., are being held without bond. Agents seized a rifle, a sawed-off shotgun and three pistols from the men when they were arrested. Authorities alleged the two men were preparing to break into a gun shop to steal more.

Lawyer Joe Byrd, who has been hired to represent Cowart, did not immediately return a call seeking comment Monday.

Cowart and Schlesselman are charged with possessing an unregistered firearm, conspiring to steal firearms from a federally licensed gun dealer, and threatening a candidate for president.

The investigation is continuing, and more charges are possible, Cavanaugh said.