The US diplomat credited with bringing peace to the Balkans has died at the age of 69.
Ambassador Richard Holbrooke, whose parents were Jewish immigrants to the US from eastern Europe, was serving as the Obama administration's envoy to Afghanistan and Pakistan.
He was admitted to hospital with a torn aorta last week, but died on Monday after unsuccessful surgery.
Anti-Defamation League director Abraham Foxman said Mr Holbrooke was "proud of his Jewish identity and a good friend of the state of Israel. His death is a loss to the world, to America, and to the Jewish people".
Jack Rosen, chairman of the American Council for World Jewry, said: "We all feel the loss of a dedicated diplomat and friend. Dick Holbrooke was integral to peace and security in the post-Cold War era, right up to his final days."
Mr Holbrooke's father was born in Warsaw while his mother originally came from Hamburg, and escaped Germany for Argentina in 1933.
The diplomat's own interest in Judaism grew after his third wife, Kati Marton, discovered her family was Jewish and that one of her grandparents had been killed in Auschwitz. She had grown up in a Catholic family, unaware of her roots.
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 famously 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.
President Obama said: "He was a true giant of American foreign policy who has made us stronger, safer, and more respected."
Ambassador Stuart Eizenstat, who served in Europe when Mr Holbrooke was US envoy to Germany, recalled a dinner party at his Bonn residence.
Noticing a picture of a German First World War soldier, Mr Eizenstat asked who it was. "That is my Jewish grandfather," Mr Holbrooke said. "I keep it here so all of the Germans who pass through will damn well realise what they lost when they killed all the German Jews."
