Costa Rica's President Oscar Arias. AFP PHOTO/Teresita CHAVARRIA

In an opinion piece written for Costa Rican daily La Nacion, Nobel peace laureate Arias also urged the United States to lift its embargo on the communist-ruled island and close its naval base at Guantanamo Bay.

He said support from Cuba's Latin American neighbors, many of whom were ruled by dictatorships in the past, gave them "a reasonable basis to ask the Cuban government for clear signs of democratic opening."

Cuba's future has been thrust into question by Castro's temporary handover of power to his brother Raul last month after he underwent surgery for intestinal bleeding, with many wondering if it could spell the end of one of the world's last remaining communist regimes.

The United States labeled the July 31 handover of power as an unacceptable "dynastic succession." It has in recent years tightened enforcement of a more than four-decade-old trade embargo on Cuba, and has increased pressure for a transition to multiparty democracy there since the handover.

Arias -- who is seen as an icon of peace after brokering peace plans for Central American civil wars in the 1980s -- said Cubans had a right to choose their country's path.

"Cuba is -- plain and simple -- a dictatorship, and this hurts those of us who love freedom," said Arias, awarded the Nobel Peace prize in 1987.

Cuba says Castro is recovering and the Communist Party will not relinquish power whether he is ill or not.