Former US president Barack Obama has tweeted a list of books by African authors that he recommends for his annual summer reading list.

They include: Things Fall Apart by Chinua Achebe, A Grain of Wheat by Ngugi wa Thiong’o, Long Walk to Freedom by Nelson Mandela, Americanah by Chimamanda Ngozi Adichie and The Return by Hisham Matar.

Mr Obama said the authors were the "best writers and thinkers – each of whom illuminate our world in powerful and unique ways".

He made the announcement ahead of his trip to the continent, which will see him visit his ancestral home in Kenya and then head to South Africa where he will deliver the annual Mandela Day lecture.