HAVANA -- Tensions are building in Cuba in advance of next week's
                  Ibero-American summit, a meeting of heads of state from Latin America,
                  Spain and Portugal that begins Monday.

                  Government supporters blocked a planned opposition march Wednesday in
                  Havana, and there were reports of dissident arrests around the island.

                  Several small opposition groups had called for a march Wednesday morning
                  from Parque Dolores in the Lawton neighborhood of Havana to urge
                  freedom for political prisoners and to protest alleged human rights abuses by
                  President Fidel Castro's government.

                  But the four main organizers of the march were temporarily detained ahead
                  of the event, which had not been expected to draw a large show of
                  discontent.

                  Groups of men, apparently plainclothes security officials or members of Cuba's Rapid
                  Response Brigades, watched the park closely, some speaking into walkie-talkies and tracking
                  the movements of media correspondents covering the event.

                  The government placed blaring loud-speakers and brought scores of students to the staging
                  ground for the march. One student said, "We were told there would be a
                  counter-revolutionary act, and we came to support the revolution."

                  Two dissidents, and then a third, who approached television cameras were beaten,
                  then taken away.

                  The presidents of at least five countries have said they will not attend the
                  summit for various reasons.

                  Presidents of Costa Rica and Nicaragua said they won't attend because of
                  objections to Castro. The presidents of Argentina and Chile will boycott to
                  protest Spain's attempts to extradite former Chilean dictator Augusto
                  Pinochet to stand trial for alleged human rights abuses.

                  The president of El Salvador said he will not attend because his country and
                  Cuba do not have diplomatic relations.

                  Jailing of activists alleged

                 The government said the dissidents were following U.S. guidance.
                 Dissident leaders say other activists have been jailed in recent days.

                 The Cuban government has said visiting heads of state will be free to
                 meet with dissidents during the summit, but any illegal activities by the
                 activists will not be tolerated.

                  Castro: Dissidents trying to derail summit

                  Castro last week accused opposition groups of trying to derail the summit.
                  In a live television broadcast, he named various "counter-revolutionary
                  ringleaders" and denounced an alleged U.S.-sponsored plot to sabotage the
                  November 15-16 meeting.

                  Opposition leaders maintain they do not want to disrupt the summit, but will
                  try to use it to publicize their criticisms of the government.

                  Elizardo Sanchez, probably Cuba's best-known human rights activist, said
                  the crackdown Wednesday and the previous detentions of opposition
                  members constituted "the biggest wave of repression this year."

                  Cuban Vice President Carlos Lage said he wasn't surprised the government
                  opponents attempted to demonstrate. "The U.S. Interest Section trains them,
                  instructs them, tells them what to do," he said.

                  3 political prisoners given leave

                  Also Wednesday, the government allowed three prominent dissidents to
                  take rare six-hour leaves from prison to visit relatives. The three were
                  imprisoned last spring for opposition activities.

                  Meanwhile, back at Parque Dolores on Wednesday, several hundred
                  members of communist youth organizations staged a noisy pro-government
                  rally and party.

                  During the rally, speakers said they were celebrating Cuba's victory against
                  the United States in Tuesday's U.N.vote condemning the economic embargo
                  against Havana and were also extending a welcome to heads of state

                  The speakers also said they were celebrating the 480th anniversary of the
                  foundation of Havana. "The street belongs to the people, to Fidel, to the
                  Party, not to these worms," one man said, when asked why a dissident was
                  chased down the street.

                  'Down with the Yankee blockade'

                  Long live the Revolution! Long live the (Communist) Party! Down with the
                  Yankee blockade!" the crowd cried.

                  The Havana-based Commission for Human Rights reported Wednesday that
                  15 to 20 dissidents had been temporarily detained in Cuban provinces to
                  prevent their participation in opposition activities planned for this week.

                  Dissident groups said that as well as the detentions, dozens of activists had
                  received warnings from security officials, been told not to leave their homes,
                  or been ordered not to travel from the provinces to Havana.

                  Dissident groups are calling a series of meetings and declarations around the
                  annual Ibero-American event, which is being held in Cuba for the first time.

                  Anti-Castro Cuban exile groups in Florida are also said to be planning
                  protests to coincide with the summit, including a flotilla of boats near Cuban
                  waters.

                     Reporter Frida Ghitis, The Associated Press and CNN contributed to this report.