World leaders issued their condolences on Saturday after the death of former UN Secretary-General and Nobel Peace Prize laureate Kofi Annan, who died in hospital in Bern, Switzerland, aged 80.
Current UN Secretary-General Antonio Guterres voiced deep sadness at the news, describing his predecessor as "a guiding force for good."
"In many ways, Kofi Annan was the United Nations. He rose through the ranks to lead the organization into the new millennium with matchless dignity and determination.
"Like so many, I was proud to call Kofi Annan a good friend and mentor."
The UN high commissioner for human rights Zeid Ra'ad Al Hussein said he was grief-stricken.
"Kofi was humanity's best example, the epitome, of human decency and grace. In a world now filled with leaders who are anything but that, our loss, the world's loss becomes even more painful," he said. "He was a friend to thousands and a leader of millions."
Ghanaian President Nana Akufo-Addo declared a week of mourning, saying the national flag will fly at half-mast at home and in the country's diplomatic missions around the world in honor of "one of our greatest compatriots."
"Consummate international diplomat and highly respected former Secretary General of the United Nations, Mr. Kofi Annan was the first from sub-Saharan Africa to occupy this exalted position. He brought considerable renown to our country by this position and through his conduct and comportment in the global arena," the president said in a statement.
"He was an ardent believer in the capacity of the Ghanaian to chart his or her own course onto the path of progress and prosperity."
Former Ghanaian President John Mahama said, "He lived and worked for global peace, security and sustainable development in very challenging times. A proud son of Ghana and Africa."
South Africa's ruling African National Congress (ANC) said Annan was "an eminent and distinguished son of Africa."
"Annan was a great friend of the people of South Africa who played an immeasurable role in shaping the global agenda in favor of the people of the developing south," the ANC said in a statement.
"Amongst his many passions was silencing the guns on the African continent."
EU Commissioner for International Cooperation and Development Neven Mimica said he was "profoundly saddened" by Annan's death.
"He was such a great source of inspiration for all of us and will be greatly missed!" he tweeted.
British Prime Minister Theresa May said her "thoughts and condolences are with his family."
"A great leader and reformer of the UN, he made a huge contribution to making the world he has left a better place than the one he was born into," she said on Twitter.
French President Emmanuel Macron said, "France pays tribute to him. We will never forget his calm and resolute approach to matters, nor the strength of his commitments."
Spain's Prime Minister Pedro Sanchez said that "today we lose a great humanist."
"Annan... has left us but his legacy remains to keep working for peace, security and to strengthen the defense of human rights," Sanchez tweeted.
NATO chief Jens Stoltenberg said he was saddened to hear the news.
"His warmth should never be mistaken for weakness. Annan showed that one can be a great humanitarian and a strong leader at the same time," Stoltenberg wrote on Twitter. "The UN and the world have lost one of their giants."
Russian President Vladimir Putin on Saturday sent condolences to Guterres following the death of Annan.
"I sincerely admired his wisdom and courage, his ability to make informed decisions even in the most complex, critical situations. His memory will live forever in the hearts of Russians," Putin said, according to a Kremlin statement.
Russian Prime Minister Dmitry Medvedev said, "A legendary UN Secretary-General and Nobel Peace Prize winner. He always sought to put an end to armed conflict, to make fighting stop and negotiations begin. A peacekeeper of his stature will be sorely missed."
UAE Minister of State for Foreign Affairs Anwar Gargash said, "Former UN Secretary-General Kofi Annan departed this world after an impressive political career, a diplomat who distinguished himself with his performance in a demanding job under difficult circumstances."
Annan was a conscience keeper of international peace, said Indian Prime Minister Modi Narendra Modi.
"Kofi Annan's significant contribution to the MDGs (Millenium Development Goals) will always be remembered. My thoughts are with his family and admirers in this hour of grief. May his soul rest in peace," Modi tweeted.
The Elders organization, a group of statesmen co-founded by Annan which speaks out on global issues, hailed the former UN chief as "a voice of great authority and wisdom in public and private."
"The world has lost an inspiring figure – but one whose achievements will never be forgotten, and whose commitment to peace and justice will endure to inspire future generations," deputy chair Gro Harlem Brundtland said in a statement.