His resignation ends his family's six-decade hold on power in Cuba.

Mr Castro, 89, told a party congress that he is handing over the leadership to a younger generation "full of passion and anti-imperialist spirit".

His successor will be voted in at the end of the four-day congress.

Although Mr Castro has not endorsed a successor, it is widely believed the party leadership will pass to Miguel Díaz-Canel, who took over as the island's president in 2018.