By Anthony Boadle

               HAVANA (Reuters) - U.S. efforts to back opponents of Cuba's communist government were so heavily infiltrated by undercover
               agents that some had passes to the American diplomatic mission, Cuban officials said on Wednesday.

                Opponents of President Fidel Castro said they always suspected some of their colleagues were spies but
                were surprised at the large number -- 12 -- who surfaced as witnesses at last week's trials of 75 dissidents.

               The biggest surprise was Aleida Beatriz, alias Agent Vilma, who worked as the secretary of Martha Beatriz Roque, a dissident
               economist supported by U.S. diplomats in Havana. Roque received a 20-year prison sentence.

               "She (Vilma) did us a lot of damage. She had access to the finances and the archives and handed everything over to the
               government," said veteran human rights activist Elizardo Sanchez.

               Dissidents were given prison sentences of up to 28 years for treason in the trials that were condemned for their severity by foreign
               governments and international rights organizations. Cuba accused the United States of violating diplomatic conventions in its
               efforts to subvert Castro, in power since a 1959 revolution.

               Cuban Foreign Minister Felipe Perez Roque showed videotaped testimony of two undercover agents at a news conference on
               Wednesday where he accused the Bush administration of turning its diplomatic mission in Havana into the headquarters of the
               island's small opposition movement.

               "I'm an agent. Agent Tania of the Ministry of Interior," Odilia Collazo, known as the leader of the Pro Human Rights Party of Cuba,
               said in testimony taped during the trial of a dissident.

               She said she supplied the U.S. diplomatic mission with reports on human rights abuses in Cuba.

               Alleged journalist Nestor Baguer, otherwise known as Agent Octavio, who had worked for Cuba's security police since 1960, said
               he visited the U.S. Interest Section so frequently he had a special pass allowing him entry on any day.

               Baguer, 72, said he was asked by U.S. diplomats to write about power outages and food and gasoline shortages in Cuba for
               independent Cuban media published in the United States on the Internet.

               On March 14, he attended a meeting of 34 dissident journalists in the residence of the top American diplomat in Havana, James
               Cason, and was asked to head a workshop on ethics in journalism, he said.

               Baguer said U.S. diplomats gave tape recorders, shortwave radios and digital cameras to independent reporters who were paid
               from the United States by using a Canadian bank debit card called Transcard.

               "They would tell the journalists what subjects interested them," he said. "The majority of the journalists are mercenaries that
               spend their time slandering Cuba."

               Another undercover agent, Manuel David Orrio, or Agent Miguel, organized the journalists' meeting at Cason's residence and
               invited foreign correspondents to attend by calling them on the cellular phone of a U.S. diplomat.

               No one knew he was a Castro spy until he testified a week ago at the trial of Raul Rivero, Cuba's most prominent dissident poet
               and journalist, who received a 20-year prison sentence. Orrio revealed he was a military officer and had worked for the state
               security police since 1992.

               Sanchez said the appearance of the undercover agents at the trials indicated the government expected the dissidents to be put
               away for a long time since it was prepared to expose its spies.