"He no longer belongs to us, he belongs to the ages." President Obama paid tribute to Nelson Mandela on Thursday evening following the news the iconic South African leader had died.
Speaking in the White House, Obama said Mandela's mark on the world was made "through his fierce dignity and unbending will to sacrifice his own freedom for the freedom of others".
"He achieved more than could be expected of any man. Today he has gone home. We have lost one of the most influential, courageous and profoundly good human beings that any of us will share time with on this Earth."
Obama, the first black president of a country that shares with South Africa a history of racial division, added: "His journey from a prisoner to a president embodies the promise that human beings and countries can change for the better. His commitment to transfer power and reconcile with those who jailed him set an example that all humanity should aspire to, whether in the lives of nations or our own personal lives."
"The fact that he did it all with grace and good humour and an ability recognise his own imperfections, only makes the man that much more remarkable."
In Britain David Cameron led tributes Mandela tonight, saying "a great light has gone out in the world". The flag at No 10 will be flown at half-mast in honour of the former leader, who was a "hero of our time", the prime minister said.
He wrote on Twitter: "A great light has gone out in the world. Nelson Mandela was a hero of our time. I've asked for the flag at No10 to be flown at half mast."
In a more detailed statement put out by Downing Street, Cameron said: "A great light has gone out in the world. Nelson Mandela was a towering figure in our time; a legend in life and now in death - a true global hero.
"Across the country he loved they will be mourning a man who was the embodiment of grace. Meeting him was one of the great honours of my life. My heart goes out to his family - and to all in South Africa and around the world whose lives were changed through his courage."
Labour leader Ed Miliband said: "The world has lost the global hero of our age. Nelson Mandela showed us the true meaning of courage, hope, and reconciliation."