By NORBERTO SVARZMAN
El Nuevo Herald

NEW YORK -- Cuba is entering a stage of major instability, in which its society is torn apart by the huge economic differences created by the flow of dollars into a Marxist economy, the chief of the U.S. State Department's Office of Cuban Affairs said Thursday.

Concerns over what might happen in Cuba during a political transition have led Washington to negotiate in secret with the Communist government, said Michael Ranneberger, who said the Havana government has shown no sign of wanting to reach an understanding with the United States.

``There have been many secret negotiations between Cuba and the United States without a resulting change in the Cuban position,'' Ranneberger said during a panel that met at the Americas Society, a nonprofit institution whose mission is to inform the American people about the society and culture of other Western Hemisphere nations.

He emphasized that the United States is interested in achieving a stable transition to democracy in Cuba.

But now, he said, ``the situation is very unstable, with political and economic problems . . . the economy is unstable, the currency is dropping and the social structure is coming apart.''

Ranneberger said the United States must encourage change and help it to occur as quickly as possible. To achieve that goal, he said U.S. policy must ``reciprocally respond to the actions of the regime, with political and economic changes.''

The United States is encouraging people-to-people contact and is cooperating with Cuba on immigration, drugs, civil aviation and weather forecasting, he said.

``There are no immediate prospects of a political change on the island,'' Ranneberger said. But he added that Washington is aware that ``we must draw up more contingency plans for a transition or change of regime.''

Another panel member, Richard Nuccio, former director of Cuban affairs at the White House and now at Harvard University, said he supports increased people-to-people contacts between Cuba and the United States.

``Contacts among peoples are already an accepted fact, something that was unthinkable seven years ago,'' Nuccio said.

He said U.S. policy toward Cuba ``is schizophrenic, with several branches of the [U.S.] government running into each other.''

``We must lift the embargo [against Cuba] in selected areas, such as food and medicines,'' Nuccio said. ``We already did that with telecommunications, which has given Cubans greater access to the outside and permitted them to receive information.''

Jaime Suchlicki, professor of history and international studies at the University of Miami, said the United States ``cannot, and should not, lift its embargo on Cuba.'' He conceded that even in the absence of President Fidel Castro, Cubans would find it difficult ``to produce major changes.''

``I believe that [armed forces chief] Raul Castro can pick up the reins of government because of his control over the armed forces, which is total, over the State Security, which is loyal to him, and over the [Communist] party,'' Suchlicki said.

``Because of the fear that exists among the Cuban population, I doubt that an uprising will occur,'' he said. ``There can only be a limited transition, but Raul is the party's second secretary, the deputy minister, the commander of the armed forces. The succession has been set. Raul may be more willing to permit an opening [of society] but that remains to be seen.''