A secret FBI dossier on civil rights leader Martin Luther King alleges that he had a string of affairs and other "sexual aberrations", as well as links to the Communist Party.

It is dated just three weeks before Dr King's assassination in April 1968.

The file was released in a tranche of documents relating to the assassination of John F Kennedy released on Friday.

Mr Kennedy is not referenced in the file and it is not clear why it was kept secret for almost 50 years.