United Nations Secretary-General Antonio Guterres attends a wreath-laying ceremony for the 57th anniversary of the death of former Secretary-General Dag Hammarskjold at the UN headquarters in New York, on Sept. 18, 2018. The United Nations on Tuesday marked the 57th anniversary of the death of former Secretary-General Dag Hammarskjold in a plane crash while on a peace mission in Africa. (Xinhua/Li Muzi)

UNITED NATIONS, Sept. 18 (Xinhua) -- The United Nations on Tuesday marked the 57th anniversary of the death of former Secretary-General Dag Hammarskjold in a plane crash while on a peace mission in Africa.

"Despite the passage of decades, his light of idealism, integrity and action continues to illuminate our hearts and, indeed, the very soul of the United Nations," said Secretary-General Antonio Guterres at a wreath-laying ceremony.

"Dag Hammarskjold reminded us many decades ago that we are one world," the UN chief said. "We have no right to destroy it. We have no right to allow divides to fester and cause so much suffering. We have the obligation to forge solutions and to also find the truth."

"As we remember the passing of Dag Hammarskjold -- and look forward to the 73rd session of the General Assembly -- let us renew our pledge to advance peace, sustainable development and human rights for everyone, everywhere," Guterres said.

Guterres used the wreath-laying ceremony to appeal for information on the crash that killed Hammarskjold, his delegation and aircraft crew in what is now Zambia, while trying to negotiate a ceasefire agreement.

Hammarskjold was a Swedish diplomat, economist and author who served as the second secretary-general of the United Nations from April 1953 until his death in the plane crash in September 1961.

Ambassador Olof Skoog of Sweden, Hammarskjold's native country, echoed Guterres' appeal for information on how the plane crashed in the jungle.

An official investigation was recently reopened in hopes that once-sealed records might shed light on reports the aircraft was shot or somehow forced to crash.

Also on Tuesday, Guterres opened the 73rd session of the UN General Assembly, and the assembly's high-level debate with the participation of world leaders does not begin until next Tuesday, to be preceded by the Nelson Mandela Peace Summit next Monday.