Former UN chief and Peruvian Prime Minister Javier Pérez de Cuéllar has died aged 100.
Mr Pérez de Cuéllar's son told local radio station RPP he died at his home in Peru.
During his two terms as UN Secretary General, he brokered peace agreements in Latin America, Africa, Asia and the Middle East.
A key achievement was negotiating a ceasefire between Iran and Iraq in 1988 after eight years of conflict.
António Guterres, the current UN Secretary General, said in a statement that he was "profoundly saddened" by the news.
"He was an accomplished statesman, a committed diplomat and a personal inspiration who left a profound impact on the United Nations and our world," Mr Guterres added.
In a tweet, Peru's President Martín Vizcarra called Mr Pérez de Cuéllar "a full-hearted democrat who dedicated his entire life to work to enlarge our country".
Image copyright Bettmann
Mr Pérez de Cuéllar, pictured with former US President Ronald Reagan, led the UN during the final years of the Cold War
Mr Pérez de Cuéllar studied law at the Catholic University of Lima before embarking on a diplomatic career with Peru's foreign ministry.
He served in embassies across Europe and Latin America, and joined Peru's delegation to the first UN General Assembly in 1946.
At the UN he presided over the influential Security Council and, as a special representative, brokered a peace deal between Greece and Turkey in 1974, following the Turkish invasion of Cyprus.
In 1981 he was named as the UN's fifth secretary general - its first from Latin America - and led the international body during some of the most critical years of the Cold War between America and the Soviet Union.
Aside from the Iran-Iraq war, by the end of his second term in 1991, he had helped to end hostilities in Western Sahara, and civil wars in El Salvador, Cambodia and Nicaragua.
As UN chief, he also secured the withdrawal of Soviet forces from Afghanistan, and mediated Namibian independence from South Africa.
He made an unsuccessful bid for Peru's presidency in 1995, losing to the country's deeply divisive leader Alberto Fujimori.
After Mr Fujimori's resignation in 2000 amid a bribery scandal, Mr Pérez de Cuéllar briefly served as foreign minister and prime minister, helping the interim government to deliver free and fair elections.
The country's newly-elected President Alejandro Toledo later appointed him as ambassador to France.
A funeral is planned for Friday.