President [Bush] moved Saturday to tighten the longstanding U.S. trade embargo against Cuba by imposing a new ban on entry to American ports by ships that trade with the Fidel Castro regime.

Bush said that only those ships that receive special licenses from the Treasury Department would be allowed entry to U.S. ports if they continue to trade with Cuba. An Administration official said the restrictions would affect about 40 ships a year that load and unload cargo in both the United Stats and Cuba.

In an apparent effort to improve his political standing among anti-communist Cuban-Americans, a crucial voting bloc in Florida, Bush also called for the Treasury Department to permit direct shipments of humanitarian food and aid packages between the U.S. and Cuba. That change, Bush said, would deny Castro's regime hard-currency payments it now receives from high shipment rates charged on packages routed through Mexico.