The allegations have been made by the Cuban opposition, and the suit is being heard in Spain due to the country's willingness to try genocide cases irrespective of the nationality of the accused.
"Castro is accused of genocide, crimes against humanity, torture and terrorism, including revolutionary terror on the island and the deliberate suffocation of Brigade - 2506 members captured in April 1961," he said.
He said the suit charged that "upon seizing power on the island, Castro began to carry out repressive policies, violating the rights and freedom of the islanders."
The document claimed that around half a million people have gone through concentration camps in Cuba since Castro came to power in 1959, and that some 16,000 people have been executed.
