ANITA SNOW
  Associated Press

  HAVANA - Fidel Castro said Saturday he was pleased the top American diplomat here tried to defuse a plane hijacking in recent days, but still accused U.S. Interests Section chief James Cason of encouraging dissidents now on trial for state security crimes.

  "No one can deny that the chief the Interests Section arrived with instructions to carry out provocations of all kinds against Cuba," Castro said on a government television show that began Friday and wrapped up early Saturday.

  "Their masters must be infuriated," said Castro, making clear he considered U.S. officials to be the true leaders of the 80 opponents now on trial. The statements, coming late in a broadcast discussing a pair of hijackings earlier in the week, were Castro's first public comments on the dissident crackdown that began last month.

  Castro did tip his hat to Cason nonetheless. Cason traveled to the Havana airport early Tuesday to try to persuade the hijacker of a passenger plane to give up his bid to go to the United States.

  Later in the week, Cason asked the island's state-run media to broadcast and publish a statement warning Cubans that if they hijacked a plane or boat to the United States they would be arrested, prosecuted and then kicked out of the country after serving a long sentence.

  Gunmen hijacked a Cuban ferry and headed toward Florida but returned on Thursday to the island, where authorities later arrested them and freed nearly 50 passengers. The man who hijacked the plane surrendered Tuesday in Florida after releasing all 31 people aboard.

  "I have not changed my opinion about Mr. Cason, but I must recognize nevertheless that he has fulfilled the instructions of the Department of State with absolute
  seriousness, efficiency, rapidity, decisiveness," Castro said.

  The crackdown of local opponents Havana accuses of working with American officials began when Cuba criticized Cason for his active support of the island's opposition. It ended several years of relative government tolerance.

  Most of the defendants were tried on Thursday and Friday in closed-door court sessions around the country. The trials are expected to end Monday with sentences issued within days. Life sentences are being sought for at least a dozen of those on trial.

  Although international media has been excluded from the trials, family members attending the proceedings said several star witnesses for the state have revealed they were government agents who infiltrated opposition ranks.

  During Friday's trial of well-known independent journalist Raul Rivero, two men he had long known as fellow reporters - Manuel David Orrio and Nestor Baguer - revealed they were infiltrators and testified against him, said Rivero's wife, Blanca Reyes. Prosecutors have sought a 20-year prison sentence for Rivero on charges of working with a foreign power to undermine the government.

  Relatives of dissident economist Marta Beatriz Roque said that during her trial on Thursday, her secretary revealed that she, too, was an undercover agent.

  At least eight such infiltrators have testified thus far during trials around the island, said veteran rights activist Elizardo Sanchez.

  The agents' testimony appears aimed at lending credibility to the trials while sowing doubt and suspicion among dissidents who remain free, said Sanchez, of the
  non-governmental Cuban Commission on Human Rights and National.

  The dissidents, rounded up beginning March 18, include leaders of independent labor unions and opposition political parties, as well as pro-democracy activists involved in a reform effort known as the Varela Project.

  International rights groups have condemned the crackdown. The U.S. State Department has called the proceedings a "kangaroo court."