US President Barack Obama said on Thursday the world was not likely see a man such as Nelson Mandela again. He said Mandela's commitment to the peaceful transfer of power during South Africa's transition to democracy inspired the world.

"We've lost one of the most influential, courageous and profoundly good men. He no longer belongs to us; he belongs to the angels.

"I am one of the countless millions who drew inspiration from Mandela. The first political thing I did was protest against apartheid. I studied his words and writings. So long as I live I will do what I can to learn from him."

Mandela passed away at 8.50pm on Thursday.

Obama said South Africa was an example to the world.

"We won't likely see the likes of Mandela again, and it falls to us to follow his legacy: never discount the difference that one man can make."

'A great light has gone out'
United Kingdom Prime Minister David Cameron, said: "A great light has gone out in the world. Nelson Mandela was a hero of our time. I've asked for the flag at No. 10 to be flown at half mast."

Bill Clinton, former US president, said Mandela's enduring legacy will be the "embracing of our common humanity".

"Nelson Mandela taught us so much about so many things. Perhaps the greatest lesson, especially for young people, is that, while bad things do happen to good people, we still have the freedom and responsibility to decide how to respond to injustice, cruelty and violence and how they will affect our spirits, hearts and minds.

"In his 27 years of imprisonment, Mandela endured physical and emotional abuse, isolation and degradation. His trials purified his spirit and clarified his vision, giving him the strength to be a free man even behind bars, and to remain free of anger and hatred when he was at last released.

"Mandela's enduring legacy is that, under a crushing burden of oppression he saw through differences, discrimination and destruction to embrace our common humanity," said Clinton.

United Nations secretary general Ban Ki-moon, said: "No one did more in our time for the values and aspirations of the UN."

'Grace and courage'
Microsoft founder Bill Gates said Mandela's "grace and courage" had changed the world.

"Every time Melinda and I met Nelson Mandela, we left more inspired than ever. This is a sad day," Gates said.

Former US president George HW Bush, said in a statement: "Barbara and I mourn the passing of one of the greatest believers in freedom we have had the privilege to know. As president, I watched in wonder as Nelson Mandela had the remarkable capacity to forgive his jailers following 27 years of wrongful imprisonment – setting a powerful example of redemption and grace for us all. He was a man of tremendous moral courage, who changed the course of history in his country."

Israeli Prime Minister Benjamin Netanyahu said in a statement: "Nelson Mandela was of the most honourable figures of our time. He was the father of his people, a man of vision, a freedom fighter who rejected violence. He set a personal example for his people in the long years he spent in prison. He was never arrogant. He worked to mend the tears in South African society and with his character managed to prevent outbursts of racial hatred. He will be remembered as the father of new South Africa and as an outstanding moral leader."

'One of the great forces for freedom'
Former US president George W Bush in a statement said: "President Mandela was one of the great forces for freedom and equality of our time. He bore his burdens with dignity and grace, and our world is better off because of his example. This good man will be missed, but his contributions will live on forever."

"The name Mandela stirred our conscience and our hearts. It became synonymous with the pursuit of dignity and freedom across the globe. Today, a great light has been extinguished. The boy from the Transkei has finished his long walk. His journey transformed not just South Africa, but humanity itself. As we mark his passing, we give thanks for the gift of Nelson Mandela. We ask that his spirit continues to inspire, guide and enlighten us as we strive to bring freedom and dignity to the family of man, our brothers and sisters, across the world," said Ireland's Prime Minister Enda Kenny. 

New Zealand's Prime Minister John Key said in a statement: "Nelson Mandela was an inspirational leader, and a remarkable man ... For years he symbolised South Africa's hope for a future free from apartheid. Mr Mandela was a force for change, not only in South Africa, but around the world."

Meanwhile, Indian Prime Minister Manmohan Singh hailed Mandela as a "true Gandhian" who would continue to inspire future generations after his death.

"A giant among men has passed away. This is as much India's loss as South Africa's. He was a true Gandhian," Singh's office tweeted after the news of Mandela's death.

"His life and work will remain a source of eternal inspiration for generations to come. I join all those who are praying for his soul."

In a separate statement, Indian President Pranab Mukherjee hailed Mandela as "a statesman, world leader and icon of inspiration of humanity".

Indian independence hero Mahatma Gandhi had his political baptism in South Africa after arriving there in 1893, with his experience of racism in the country shaping his future political activism back home.

India was the first country to sever trade relations with the apartheid regime in Pretoria back in the 1940s. – Additional reporting by Reuters