The Bush administration says it plans to go after anyone who does business with 10 companies controlled by the Cuban government.

  BY NANCY SAN MARTIN

  In the latest move to obey President Bush's orders to tighten U.S. sanctions on Havana, the Treasury Department on Monday identified 10 companies owned by the Cuban government and warned that anyone doing business with them could face criminal charges.

  Treasury Secretary John Snow told The Herald his department is also considering tightening the restrictions on cash remittances that Cuban Americans send to relatives on the island. The department also is considering revoking the authorization for legal travelers to bring back up to $100 worth of Cuban goods, including cigars and rum -- a side benefit of travel to Cuba.

  In a separate action, Treasury officials also announced that three cases are under investigation by the U.S. attorney's office in Miami for possible criminal violations. They declined to discuss the cases but federal sources said it was tied to an annual summer sailboat race to Cuba out of Key West. Several participants in last year's race were flagged by authorities for possible violations.

  The department's actions were part of the heightened enforcement of U.S. commercial and travel sanctions on Cuba emerging from President George W. Bush's order in October to tighten restrictions in place against President Fidel Castro's government since the 1960s.

  The 10 Cuban government firms identified by Treasury allegedly help U.S. residents break the bans on most travel and trade with Cuba by offering travel packages to
  people who do not qualify, plus selling products via the Internet that are delivered to island residents for a fee.

  `EASY ACCESS'

  ''These companies have been providing easy access to Cuba to those U.S. individuals who chose to break the law,'' Snow said in a speech to Cuban Americans in Coral Gables. ``Today's action will put a stop to that, and a stop to another illegal pathway for U.S. dollars to Castro's wallet.''

  The companies and subsidiaries identified were: Havanatur S.A., a leading tour operator in Cuba with branches in Argentina, the Bahamas and Chile; Cubanacán Group, a Cuban tourist group with branches in the Netherlands and England; CIMEX, which is owned by the Cuban government; and 2904977 Canada Inc., a CIMEX subsidiary based in Montreal.

  Also named was La Compañia Tiendas Universo S.A., an Internet company owned by Cubanacán that sells items such as food, appliances and cosmetics for delivery to Cubans on the island.

  Some of the Cubanacán and Havanatour branches are known to have arranged flight and hotel reservations for U.S.-based travel agencies that lack the U.S. permits
  required for doing business with Cuba.

  Authorities said those U.S. companies, as well as people who purchase tour packages or products from the U.S. or Cuban firms, could face civil and criminal penalties and have their bank accounts frozen under the U.S. Trading with the Enemy Act. Penalties can reach 10 years in prison and hefty fines.

  ''You as the consumer are now on notice: to do business with them is to provide support to the Castro regime,'' Juan Zarate, Treasury's deputy assistant secretary, said in an interview with The Herald.

  Americans, with some exceptions, are prohibited from traveling to Cuba or conducting business with the communist-ruled nation. Cuban-Americans are allowed annual
  trips for family reunifications. Exceptions are also available for journalists, academic and religious groups, and several dozen U.S. firms have permission to arrange their travel.

  Officials said that since heightened enforcement of U.S. sanctions began in October, authorities have prevented 275 travelers from boarding Cuba-bound flights after
  discovering that they did not have proper licenses.

  Also, more than 300 civil violation notices have been sent to suspected illegal travelers and three administrative law judges have been assigned to 111 cases, including 63 that resulted in settlement payments.

  CASH FOR RELATIVES

  Snow also told The Herald his department would ''take a hard look'' at rules that now allow Cuban Americans to send as much as $1,200 a year to relatives on the island, to determine if the money is really ``going to where it's supposed to.''

  Bush also has ordered a thorough review of U.S. policy and in October created a Cabinet-level Commission for Assistance to a Free Cuba, to make recommendations for how Washington should deal with the island after Castro leaves power.

  ''The president has been pretty clear in his views on Castro,'' Snow said. ``He is committed to the Cuban people even as he loathes and detests the regime. As we
  uncover violations of U.S. law, we're going to act on them.''

  Herald staff writer Larry Lebowitz contributed to this report.