"Honestly speaking, we are in a mess", Annan said at the time.
Mr Annan filled a number of roles in his long diplomatic career at the United Nations from peacekeeping operations to senior managerial positions and was the first secretary general to emerge from the ranks of the organisation's staff.
Foreign Secretary Alan Peter Cayetano said the Philippines will remember Annan as a "champion of humanity". He studied at University of Science and Technology in Kumasi and completed his undergraduate work in economics at Macalester College in the United States in 1961. "And, "... Was a guiding force for good".
Portuguese Prime Minister Antonio Costa said as the United Nations chief, Annan "was a world leader in the cause of peace, development and human rights".
He was in charge of the United Nations during the time of the Iraq War, and the arguments over the military action made him a face many people recognised. In 2001, Annan won a Nobel Peace Prize for his fight against AIDS in Africa, his stance against global terrorism, and his prioritization of human rights.
Nobel Peace Laureate and former United Nations Secretary General Kofi Annan was "a conscience keeper of worldwide peace and security", said Prime Minister Narendra Modi, as many Indian leaders expressed condolences over Mr. Annan's death on Saturday.
"I am a stubborn optimist, I was born an optimist and will remain an optimist", Annan added.
Wherever there was suffering or need, he reached out and touched many people with his deep compassion and empathy.
The UN Migration Agency tweeted: "Today we mourn the loss of a great man, a leader, and a visionary".
I extend, on behalf of the entire Ghanaian nation, our honest, heartfelt condolences to his beloved widow, Nane Maria, and to his devoted children, Ama, Kojo and Nina, on this great loss.
He was recently pictured meeting Zimbabwean President Emmerson Mnangagwa in his role as chair of The Elders - an independent group of global leaders working together for peace and human rights.