Opening a three-week synod of African bishops, he said political colonialism was over.

But he said the developed world continued to export materialism - which he called "toxic spiritual rubbish" - to the continent.

Almost 200 bishops from 53 African states have gathered to discuss how the Catholic Church can help resolve the continent's social injustices and wars.

The Pope says he will attend as many of the working sessions of the synod as possible, his other duties permitting.