UN nuclear watchdog chief Rafael Grossi arrived in Tehran Friday for discussions with officials after his agency’s inspectors in Iran found uranium particles enriched to just under weapons-grade level. The visit by the head of the International Atomic Energy Agency comes with the Vienna-based organisation seeking to get Iran to increase cooperation over its nuclear activities. Grossi was greeted at the airport by Behrouz Kamalvandi, the spokesman for the Atomic Energy Organization of Iran and is due to meet its head, Mohammad Eslami, as well as other Iranian officials during his two-day visit. A confidential IAEA report seen Tuesday by AFP said uranium particles enriched up to 83.7 percent — just under the 90 percent needed to produce an atomic bomb — had been detected at Iran’s underground Fordo plant about 100 kilometres (60 miles) south of the capital. Tehran denies wanting to acquire atomic weapons, and last week said it had not made any attempt to enrich uranium beyond 60 percent purity, noting that “unintended fluctuations… may have occurred” during the enrichment process. The discovery came after Iran had substantially modified an interconnection between two centrifuge clusters enriching uranium, without declaring it to the IAEA. The IAEA tweeted on Thursday that Grossi would “travel to Tehran for high-level meetings at the invitation of Iran’s government”. A diplomatic source told AFP that Grossi would also meet President Ebrahim Raisi to “relaunch the dialogue” on Iran’s atomic work and to “reset the relationship at the highest level”.