U.S. President Barack Obama thanked Nelson Mandela for being his hero. Mr Obama was visiting South Africa. Although Mandela is very ill, Obama did not visit him. The White House said Obama cared about Mr Mandela's health. Obama told reporters that he didn't want to make Mr Mandela more ill. He said: "I don't need a photo op." He added: "The last thing I want to do is [get in the way] when the family is concerned about Nelson."

President Obama called Mandela a "personal hero". He said Mandela gave his life for equal rights. He also said Mandela's actions helped him in his own job. Obama said he wanted to say a big thank you to Mr Mandela. He said Mandela was a great leader and that all Americans were praying for him. Obama later told students in Pretoria to learn lessons from Mandela's 27 years in prison. He said there were "dark moments" but Mr Mandela never gave up.