VIENNA (AP) — Argentine diplomat Rafael Mariano Grossi is set to take the helm at the U.N. nuclear watchdog this week after being confirmed as its new leader.

The International Atomic Energy Agency’s general conference approved Grossi’s appointment unanimously at a special session on Monday. His four-year term begins on Tuesday.

Grossi succeeds Yukiya Amano, who died in July and was extensively involved in negotiations over Iran’s nuclear program. The 58-year-old won the support of the IAEA’s board of governors in October.

Grossi became Argentina's ambassador to the Vienna-based agency in 2013 and was previously the IAEA's chief of cabinet under Amano.

Grossi said that “the IAEA is a formidable institution with a unique mandate, and I want to ensure that it delivers at its full potential.”