"Cuba has at least a limited offensive biological warfare research and development effort," said John Bolton, undersecretary of state and the department's top official on weapons proliferation.
Cuba has shared its technologies with "other rogue states," Bolton said. He did not identify the states, but he noted that President Fidel Castro last year had visited Iran, Syria and Libya, all of which are on the State Department's list of states that sponsor terrorism.
"We are concerned that such technologies could support biological weapons programs in those states," Bolton said in a speech to the Heritage Foundation, a conservative Washington think tank.
The Cuban government and Americans who want a change in U.S. policy toward the island immediately denounced Bolton's charges. They portrayed the comments as a politically motivated attack by an administration intent on courting Hispanics and conservatives.
"This is a statement without evidence," said Wayne Smith, of the Center for International Policy in Washington. "It's utterly irresponsible to make this kind of a statement without evidence and at a time when we should not be looking for new enemies."
Bolton said Cuba's biological warfare program has grown out of "a well-developed and sophisticated biomedical industry, supported until 1990 by the Soviet Union."
State Department spokesman Richard Boucher would not comment further on the accusations