Cuban Vice President Carlos Lage plans to visit Tokyo in early October at the Japanese government's invitation to discuss with Japanese leaders ways to strengthen hitherto estranged relations between the two countries, diplomatic sources said Friday.

The sources said that the 48-year-old Lage, who is widely regarded to be one of the most likely future successors to the aging Cuban President Fidel Castro, 73, will be the highest-ranking Cuban official ever to make an official visit to Japan.

The sources also said that Racardo Alarcon, the 63-year-old head of the Cuban national assembly, also plans to visit Japan in November at the invitation of the Diet.