Yukiya Amano made his assessment in a regular update to the International Atomic Energy Agency’s board of governors, confirming a confidential report distributed to member states last month.

He said “Iran is implementing its nuclear-related commitments under the Joint Comprehensive Plan of Action,” referencing the official name of the 2015 deal.

In May 2018, the U.S. unilaterally withdrew from the deal and reimposed sanctions on Tehran.

The other signatories — Germany, France, Britain, Russia and China — are trying to keep alive the deal, which offered Iran economic incentives.