BY NANCY SAN MARTIN

  WASHINGTON - U.S. officials have denied permission for travel to Cuba to organizers of last year's unprecedented U.S. Food and Agribusiness Exhibition in Havana, as part of the Bush administration's reply to the dissident crackdown on the island.

  In a letter made public Tuesday, the Treasury Department's Office of Foreign Assets Control, which issues the travel licenses, stated that two travel requests were denied "based on foreign policy guidance received from the Department of State.''

  Exhibition organizers had applied for separate licenses to travel to Cuba to organize a second food and agricultural fair in Havana as well as a healthcare exhibition.

  The letter dated June 2 was sent to Peter Nathan, the organizer of the events. He could not be reached for comment Tuesday.

  A State Department official said: "We always look at these requests with an eye toward circumstances on the ground in Cuba. Certainly, circumstances in Cuba have changed drastically over the past few months. Clearly, events such as agricultural and health fairs are not appropriate in light of the mass arrests.''

  Taylor Griffin, a Treasury Department spokesman, said the agency is committed to ''full and fair enforcement'' of U.S. policy toward Cuba and -- repeating comments previously made by President Bush -- would not issue licenses for events that would help ``line the pockets of Fidel Castro and his cronies.''

  The Bush administration released new travel rules on March 24, following the arrests of scores of government opponents across the island. Summary trials were held in April and the government ultimately sentenced 75 dissidents to up to 28 years in prison.

  When the new travel restrictions were released, officials said the rules were in response to Bush's ''Initiative for a New Cuba'' announced last May. The president's initiative is intended "to encourage freedom within Cuba, make life better for the Cuban people and give the Cuban people greater control of their economic and political destiny.''

  Other revisions include no longer issuing permits to organizations that take individuals to Cuba to participate in ''educational'' exchanges that are not related to academic course work and allowing travelers with relatives in Cuba to carry as much as $3,000 in household remittances, up from $300, each quarter. The increase in the cash flow is intended to help up to 10 households per traveler receive funds, some of which is meant to reach government opponents.

  The U.S. Food and Agribusiness Exhibition, held in September, included 923 representatives from 291 U.S.-based companies and state organizations, according to the U.S.-Cuba Trade and Economic Council in New York. An estimated $92 million in contracts and agreements were signed between exhibition participants and the Cuban government.