VIENNA (Reuters) -"Fluctuations" at Iran's Natanz plant pushed the purity to which it enriched uranium to 63%, higher than the announced 60% that complicated talks to revive its nuclear deal with world powers, a report by the U.N. nuclear watchdog said on Tuesday.
Iran made the shift to 60%, a big step towards nuclear weapons-grade from the 20% previously achieved, last month in response to an explosion and power cut at Natanz that Tehran has blamed on Israel and appears to have damaged its enrichment output at a larger, underground facility there.