Iran has complied with a deadline set by its landmark nuclear deal with world powers by removing hundreds of centrifuges, machines that enrich uranium, from a site buried deep inside a mountain, the U.N. atomic agency said on Monday. The deal reached between six powers and Iran in 2015 stated that no more enrichment would take place at the Fordow site near the holy city of Qom for 15 years, but that Iran could keep just over 1,000 centrifuges there for other uses.