The head of the United Nations's nuclear watchdog has died, the International Atomic Energy Agency announced Monday.
“The Secretariat of the International Atomic Energy Agency regrets to inform with deepest sadness of the passing away of Director General Yukiya Amano,” the IAEA said in a statement.
Yukiya Amano had been expected to step down from his position Monday because of an illness that had affected him over the last year.
The 72-year-old Japanese diplomat had held the position of IAEA director general since 2009.
He guided the agency through a tumultuous time for nuclear development including the negotiation of the 2015 multilateral Iran nuclear deal.
Amano's death comes amid escalating tensions between the U.S., which left the agreement last year, and Iran.
No timeframe for appointing a new chief was given by the IAEA.