The US diplomat credited with bringing peace to the Balkans has died at the age of 69.
Ambassador Richard Holbrooke, who was of Jewish descent, was serving as the Obama administration's envoy to Afghanistan and Pakistan.
He was admitted to hospital on Friday for a torn aorta, but died after unsuccessful surgery.
A diplomat since the 1960s, Mr Holbrooke worked for every Democrat president since John F Kennedy. He served in Vietnam in the 1960s, and later as ambassador to Germany. Most notoriously he was Assistant Secretary of State for Europe under President Bill Clinton.
It was in this role that he brokered the Dayton Accords in 1996, a peace deal for the conflict-ridden Balkans region.
Both Mr Holbrooke's parents were immigrants to the United States. His father was born in Warsaw to a Russian Jewish family, while his mother, who was also Jewish, originally came from Hamburg, and escaped Germany for Argentina in 1933 as the Nazis were consolidating power.
His third wife, Kati Marton, grew up in a Roman Catholic family but later in life discovered her family was Jewish and that one of her grandparents had been killed in Auschwitz.
President Obama said he was "deeply saddened” by Mr Holbrooke’s death.
He said: “He was a true giant of American foreign policy who has made America stronger, safer, and more respected.
“He was a truly unique figure who will be remembered for his tireless diplomacy, love of country, and pursuit of peace
Britain’s Foreign Secretary William Hague also paid tribute to a man he described as “one of the best and the brightest of his generation”.
Mr Hague said: “He has served his nation with distinction and integrity.”