Argentina’s Rafael Grossi was elected on Tuesday to head the UN’s nuclear watchdog, which is tasked in particular with monitoring the implementation of the increasingly shaky Iran nuclear deal. Grossi beat Romanian diplomat Cornel Feruta to become director general of the International Atomic Energy Agency (IAEA) following the death of the former head Yukiya Amano of Japan in July. The election of Grossi, Argentinia’s ambassador to the IAEA, comes at a critical time for the Vienna-based agency as Iran is decreasing its commitments under the 2015 landmark deal.