UNITED NATIONS - United Nations Secretary-General Antonio Guterres on Monday described Nelson Mandela as a "moral compass," calling for honoring the former South African president's legacy by taking action.

"Nelson Mandela was a healer of communities and a mentor to generations," Guterres said in his message to mark the Nelson Mandela International Day, which falls on Monday.

"He remains a moral compass and reference to us all," the UN chief noted, adding that Mandela showed that "each and every one of us has the ability and responsibility to build a better future for all."

"Our world today is marred by war; overwhelmed by emergencies; blighted by racism, discrimination, poverty, and inequalities; and threatened by climate disaster. Let us find hope in Nelson Mandela's example and inspiration in his vision," Guterres said.

The best way to honor Mandela's legacy is by taking action, the UN chief said.

"By speaking out against hate and standing up for human rights. By embracing our common humanity -- rich in diversity, equal in dignity, united in solidarity. And by together making our world more just, compassionate, prosperous, and sustainable for all," he said.

Under the theme of taking action and inspiring change, the Nelson Mandela International Day was celebrated through an informal meeting of the General Assembly at the UN Headquarters in New York on Monday.

At the special event, UN officials, representatives of member states, among others, delivered remarks in memory of Nelson Mandela, stressing the relevance of his legacy to the present time.

UN Deputy Secretary-General Amina Mohammed said that Mandela has been an inspiration for her ever since she was a young person trying to find her path.

"I have taken to heart his profound lesson that we all have the ability -- and responsibility -- to take action," she said.

The best tribute to Mandela is to realize the promise of the Sustainable Development Goals, "to stand united against hate, and to work for peace, prosperity, and human rights for all, on Mandela Day and every day," she said.

In his remark, Abdulla Shahid, president of the UN General Assembly, underscored that Mandela's fight against apartheid was in fact a fight for a better world, in which the freedom, justice and dignity of all were respected.

Citing multiple challenges including conflict, global pandemic and global food security crisis at the very moment, he said that it's not the time for despair.

"No matter the challenges and obstacles, we must persevere with conviction, with determination, and with hope," Shahid said, noting that this is what Mandela would have wanted and fought for.

In November 2009, the UN General Assembly declared July 18, Mandela's birthday, as Nelson Mandela International Day in recognition of the former South African president's contributions to peace and freedom.