After hours of negotiations in Vienna, July 13, the foreign ministers of the six world powers and Iran had still not progressed toward overcoming the differences still in the way of their signing a final accord on Iran’s nuclear program by the July 20 deadline. Tehran rejects demands for a cap on its centrifuges and enriched uranium quotas, and refuses to halt construction of the Arak heavy water plant or shut down the underground enrichment facility שא Fordo.