Cuba's President Fidel Castro injured one of his knees and an arm when he tripped and fell as he returned to his seat after making a speech at a graduation ceremony.

The 78-year-old was picked up by bodyguards who helped him into a chair after the fall at the ceremony for art instructors at Santa Clara in the centre of the country.

The president asked for a microphone and told the crowd of about 30,000 people that it was possible he had sustained a fracture in the knee and maybe in an arm.