Washington — Hoping to try to revive diplomatic efforts to get the United States and Iran back to the table, and to keep the 2015 nuclear deal alive through the 2020 US elections, three European powers and the European Union foreign policy chief on Monday expressed regret as the United Nations atomic watchdog agency confirmed that Iran had resumed enrichment at the underground Fordow facility.

The fortified site, built into a mountain near Qom, had been converted into a research center where no enrichment was to take place for 15 years under the 2015 accord that the Donald Trump administration withdrew from last year. But Iran announced last week that it was resuming enrichment at Fordow as the fourth step of reducing its commitments under the Joint Comprehensive Plan of Action (JCPOA) until the remaining parties to the deal — the United Kingdom, France, Germany, Russia and China — find ways to compensate Iran for the United States’ reimposition of crippling sanctions on its banking and energy sectors.

The International Atomic Energy Agency (IAEA), in a 7-page confidential report issued on Monday and seen by Al-Monitor, confirmed that Iran had resumed enrichment at Fordow on Nov. 9. The new report said that Iran’s stockpile of enriched uranium had grown to 372 kilograms (820 pounds) — which marks the addition of 130 kilograms (286 pounds) since the IAEA’s last quarterly report in late August, and exceeds a 300-kilogram (661-pound) cap on Iran’s stockpile of low enriched uranium set by the JCPOA.

The IAEA has also “detected natural uranium particles … at a location not declared to the agency,” the new IAEA quarterly report said.