Fidel Castro says President Bush is plotting with Cuban American exiles to kill him.
The Cuban leader adds that if the U.S. does try to oust him, he'll die fighting.
Castro made the comments in a five-and-a-half-hour speech at a conference of regional activists who oppose the Free Trade Area of the Americas.
He didn't provide details of the alleged plot.
The Cuban leader has been insisting over the past year that hardline Cuban exiles in Miami are pressuring the Bush administration to invade Cuba. However, the U.S. denies the charge.
Castro has accused past administrations of similar plots. During his early years in power, there were documented cases of U.S.-backed attempts on his life.
However, President Gerald Ford signed an executive order in 1976 banning the U.S. assassination of foreign leaders.