Secretary-General Ban Ki-moon says Nelson Mandela was "a giant for justice" whose "selfless struggle for human dignity, equality and freedom" inspired many people around the world.
"No one did more in our time to advance the values and aspirations of the United Nations," he told reporters soon after Mandela's death was announced Thursday.
Ban said he was deeply touched when he met Mandela in his residence in South Africa in February 2009.
"When I thanked him for his life's work, he insisted the credit belonged to others," Ban said. "I will never forget his selflessness and deep sense of shared purpose."
"Nelson Mandela showed what is possible for our world, and within each one of us, if we believe a dream and work together for justice and humanity," the secretary-general said. "Let us continue each day to be inspired by Nelson Mandela's lifelong example to keep working for a better and more just world."
The U.N. Security Council interrupted a meeting on the tribunals for former Yugoslavia and Rwanda and stood for a minute in silent tribute to Mandela.
Argentina's U.N. Ambassador Maria Cristina Perceval, who had been speaking, called Mandela "a man who gave hope to the entire world."
"Good men and women, men such as Mandela resisted and taught us to resist fear ... to resist oblivion," she said.
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