The eldest son of Cuban revolutionary Fidel Castro killed himself in Havana after battling months of depression. Fidel Castro Diaz-Balart, 68, a nuclear physicist, was found dead on Thursday (1 February), said the island's state media.

Popularly known as "Fidelito" and striking a close resemblance to his father, he was the first-born and only son of Castro and his first wife, Mirta Diaz-Balart. Mirta was the daughter of a prominent politician of the pre-revolution era.

The deceased Castro, formerly trained in the Soviet Union, shot himself in the head in Havana, according to local reports. He, however, had received medical treatment as an outpatient for depression in recent months before he decided to take his own life.

"His delicate health situation required hospitalisation and then continued with outpatient follow-ups as he reintegrated himself back into society," a report on Cuban state television said.

Tall and bearded, he was born in 1949, a decade before his father went on to lead a revolution carving a communist state.

The young Castro, married to a Russian woman, was sent by his mother to visit his father following the takeover. But, the father Castro did not return the boy, leading to claims by the mother's family members' that the child was kidnapped.

The junior Castro was a science advisor to Cuba's Council of States when he died. According to his official profile, he held degrees in Physical- Mathematics Sciences and Physics, and was an expert in nuclear Physics. He has also penned several academic books and represented Cuba in various international platforms.

Fidelito performed a key role in Cuba's nuclear programme but, was later removed from his positions when there was a fallout with his father. He reemerged in 2008 making public appearances when his uncle Raul Castro took charge as president.

Cuba's state television said Fidelito's funeral would be decided by his family members.

Fidel Castro eldest son
Fidel Castro Diaz-Balart, son of Cuba's former president Fidel Castro, talks to Argentine human right activist in this file photo Claudia Daut/Reuters