BERLIN (AP) — The United Nations’ atomic watchdog says in a report that Iran has enriched uranium to slightly higher purity than previously thought due to “fluctuations” in the process. The report underscores the challenges diplomats face in ongoing talks to bring the United States back into the nuclear deal with Tehran. The International Atomic Energy Agency confirmed Wednesday that recent samples “showed an enrichment level of up to 63% … consistent with fluctuations of the enrichment levels experienced in the mode of production at that time.” Iran has been steadily violating the restrictions of the the landmark 2015 deal after then-President Donald Trump pulled the U.S. out unilaterally in 2018 and reimposed crippling sanctions.