Tributes pour in for former UN chief and Nobel laureate Kofi Annan

From his native Africa to the United States, tributes continued to pour in from around the world today after UN chief, Nobel peace laureate, and "diplomatic rock star" Kofi Annan died at the age of 80.

The Ghanaian national was a career diplomat who projected quiet charisma and was widely credited for raising the world body's profile in global politics during his two terms as head of the UN from 1997 to 2006.

The first secretary general from sub-Saharan Africa, Annan led the United Nations through the divisive years of the Iraq war and was later accused of corruption in the oil-for-food scandal, one of the most trying times of his tenure.

Annan "astutely guided the United Nations organisation into the 21st century defining an ambitious agenda that had made the UN truly indispensable to peace, prosperity and human dignity around the world," Annan's successor as UN secretary general, Ban Ki-moon, said in a statement.

Annan's family said he had passed away peacefully on Saturday after a short illness.

Annan, who lived not far from the UN European headquarters in Geneva, died in a Bern hospital, Swiss media reported.

His foundation told the ATS news agency Sunday his funeral would be a private event, but did not provide further details. It said a separate UN ceremony would be held at a later date.

Current UN chief Antonio Guterres described his predecessor as "a guiding force for good".

"In many ways, Kofi Annan was the United Nations," he said. "He rose through the ranks to lead the organisation into the new millennium with matchless dignity and determination." The UN said it would fly flags at half mast at all of its locations around the world through Tuesday.

And Ghana's President Nana Akufo-Addo announced a week of mourning for "one of our greatest compatriots".

In 2001, as the world was reeling from the September 11 attacks in the United States, Annan was awarded the Nobel Peace Prize jointly with the world body "for their work for a better organised and more peaceful world".

Another Nobel laureate, retired South African archbishop Desmond Tutu, described Annan as "an outstanding human being who represented our continent and the world with enormous graciousness, integrity and distinction." - 'Diplomatic rock star'