Spokesman for the Atomic Energy Organization of Iran (AEOI), Behrouz Kamalvandi, said Wednesday that preparations for the fourth stage of a reduction in Iran’s commitments to the Joint Comprehensive Plan of Action (JCPOA), also known as Iran nuclear deal, have begun.

Russia will deliver a sophisticated short-range air-defense missile system to Serbia despite U.S. warnings of possible sanctions against the Balkan country if the transaction goes through.

The spokesman for the Atomic Energy Organization of Iran (AEOI) says with the new centrifuges installed following the third step that Iran took to reduce its commitments under the 2015 nuclear deal, the country’s enrichment capacity is to reach the level it was before signing the agreement.