Cuba's communist authorities have freed one of the island's longest-serving political prisoners, Ernesto Diaz Rodriguez, after he completed 22 years of his 40-year sentence, a senior judicial official said Tuesday.

Lizzel Santana Gomez told Reuters that Diaz, who is in his 50s, left prison Friday. She said he had been freed for humanitarian reasons because he was ill.Diaz was arrested in 1968 and subsequently sentenced to 40 years for involvement in attempts to overthrow Cuba's government.