IAEA chief Yukiya Amano dies aged 72
Amano spent years negotiating with Iran on more intrusive nuclear inspections, and he oversaw the implementation of the nuclear agreement that Tehran finally agreed to in 2015.
The IAEA did not say when and of what cause the Japanese diplomat died at the age of 72, but it confirmed that he had already drafted a letter of resignation.
Amano's office had announced last September that Amano had undergone an unspecified medical procedure. Since his return to work, he had appeared frailer.
Amano first assumed the office of IAEA director general in 2009, after having served as a senior arms control diplomat in the Japanese Foreign Ministry.
In 2017, IAEA member countries confirmed him for a third term in office that was set to last until December 2021.
"I am very proud of our achievements, and grateful to member states and agency staff," he had planned to write in his resignation letter, his office said.
Amano was a strong supporter of dialogue and diplomacy in international efforts to curb and monitor Iran's nuclear programme.
He also steered the IAEA through the aftermath of the 2011 nuclear disaster at Japan's Fukushima power plant, which was caused by an earthquake and tsunami.
In a first reaction, EU chief diplomat Federica Mogherini remembered Amano as a "man of extraordinary dedication and professionalism, always at the service of the global community in the most impartial way."
"It has been for me a great pleasure and privilege working with him," said Mogherini, who played a key role in negotiating the Iran deal along with foreign ministers of major powers.
