From Kelly Wallace
CNN Washington Bureau

WASHINGTON (CNN) --As former President Carter begins his historic visit
to Cuba, hoping to ease tensions between Washington and Havana, President
Bush is preparing to toughen his strategy for dealing with Cuban President
Fidel Castro, CNN has learned.

Bush will deliver a speech next week outlining the United States' policy toward Cuba
and then travel to Miami to honor Cuban Independence Day, aides told CNN.

The Bush administration has already made one move, with a senior State Department
official last week publicly accusing Castro of developing limited biological weapons.

Cuba strongly denied the charge, but Secretary of State Colin Powell repeated the
accusation in an interview Sunday with Russian television.

"We know that Cuba has been doing some research with respect to biological
offensive weapons possibly, and so we think that it is appropriate for us to point out
this kind of activity," Powell said.

The president has made clear he believes that easing the decades-old trade and travel
restrictions on Cuba would only help Castro stay in power.

Otto Reich, Bush's assistant secretary of state for Western Hemisphere affairs, said
in early March, "We are not going to help Fidel Castro stay in power by opening up
our markets to Cuba."

Reich conducted a top-to-bottom review of U.S. policy toward Cuba that is nearly
completed or "relatively mature," as one aide described it.

While aides were tight-lipped about what Bush would announce next Monday, they
did not rule out the following possibilities:

     Further tightening travel restrictions to the island.

     Increasing aid to help bolster Cuban dissidents.

     Stepping up efforts to ensure that U.S. government broadcasts get to the Cuban
     people.

     These moves would be applauded by many Cuban-American lawmakers,
     important allies for the Bush administration in the crucial battleground state of
     Florida.

     "For people to think that when you travel to Cuba that you are bringing the
     Cuban people closer to democracy, that's like believing in Santa Claus and in
     the Easter Bunny," Rep. Ileana Ros-Lehtinen, R-Florida, a strong advocate of
     the economic and travel embargo, told CNN Saturday. "Castro is never going
     to change."

     On the other side are lawmakers who agree that Castro needs to go but
     believe it is time to end what they call failed economic and travel restrictions.

     "We've tried the embargo and that doesn't seem to work," Sen. Evan Bayh,
     D-Indiana, told CNN. "That really has punished U.S. workers and producers
     by cutting off our markets and allowing them to be filled by the Canadians,
     the Europeans and others."

     U.S. officials said the president's announcement next Monday on Cuba was
     planned well before former President Carter's trip.

     Still, it will be a chance for Bush to answer any calls to ease sanctions that
     may arise following the Carter mission, and also provide a chance to appease
     those Cuban-Americans who feel the administration has so far not put enough
     pressure on Castro.

     The Bush administration chose not to block Carter's trip to Cuba, though it
     did not strongly endorse the mission either.

     U.S. officials said they asked the former president to press human rights
     issues and push for democratic reforms during his visit.

     Carter was briefed by State Department officials last week, before leaving for
     Havana. He did not speak with Bush, a senior administration official said.