HAVANA: Cuba marked the end of an era Monday with the official transfer of power from the Castro clan, in charge for six decades, to the communist country's first civilian leader, Miguel Diaz-Canel.

The transition, while hugely symbolic, is unlikely to result in dramatic policy shifts in the one-party system that Diaz-Canel, 60, has vowed to safeguard.

"The most revolutionary thing within the Revolution is to always defend the party, in the same way that the party should be the greatest defender of the Revolution," he said on Monday.

Diaz-Canel added the outgoing leader, 89-year-old Raul Castro, would still be consulted on "strategic decisions."

From retirement, Castro would give "direction and alert to any error or deficiency, ready to confront imperialism as he first did with his rifle," said the new leader.

Already Cuba's president since 2018, Diaz-Canel has now also taken the most senior position of first secretary of the Communist Party of Cuba (PCC).

The pre-determined power change at a four-day PCC congress in Havana, marks a watershed for the country of 11.2 million people, many of whom have not known a leader who was not a Castro.

Fidel Castro, still revered as the country's father and savior, led the country from 1959 to 2006, when he fell ill and his brother took over.

Diaz-Canel was born after the revolution led by the Castro siblings in the 1950s, leading in 1959 to the overthrow of dictator Fulgencio Batista.

The PCC congress was held 60 years after Fidel Castro declared Cuba a socialist state, setting up decades of conflict with the United States, which has had sanctions against the country since 1962.