The United Nations marked Nelson Mandela International Day on Wednesday with a pledge to take actions for peace and equality.

In November 2009, the UN General Assembly inaugurated July 18 to recognize the anti-apartheid leader's contributions to peace and freedom. It also was the 100th anniversary of the birth of Mandela, who died in December 2013.

UN Secretary-General Antonio Guterres said in a video message on Tuesday for Nelson Mandela International Day that Mandela was "a towering global advocate for justice and equality".

"He continues to inspire the world through his example of courage and compassion," Guterres said. "Nelson Mandela was held captive for many years. But he never became a prisoner of his past. Mandela poured his energy into reconciliation and his vision of a peaceful, multi-ethnic, democratic South Africa."

The UN chief said: "Rarely has one person in history done so much to stir people's dreams and move them to action. That struggle for equality, dignity and justice continues."

Mandela, who eventually became South Africa's first black president, was imprisoned for 27 years. His struggle against apartheid has had a profound impact on the world.

A centennial stamp was unveiled during a UN General Assembly event on Wednesday for the occasion of Mandela Day at the UN headquarters in New York, with a Mandela quote: "It is easy to break down and destroy. The heroes are those who make peace and build."

Describing Mandela as "a beacon for universal values — peace, forgiveness, humility, integrity, passion, respect and service", Guterres said at the event: "Madiba showed us that these are not just words or vague ideals, but concrete actions that we can all take."

UNGA President Miroslav Lajcak highlighted Mandela's lessons on dialogue, peace and tolerance. 

"He showed us that dialogue and negotiation should be pursued relentlessly – no matter how deep the divides, or strong the hurt," he said.

"The prophet is no longer with us. But his teachings are. And we need them – now, more than ever," he added.

On Tuesday, former US president Barack Obama used a tribute to Mandela to warn that the world had plunged into strange and uncertain times.

He also criticized climate-change denial and race-based migration policies in a speech marking the centenary of Mandela's birth at a stadium in Johannesburg.

Contact the writer at wanglinyan@chinadaily.com.cn

AFP contributed to this story.