The acting head of the UN nuclear watchdog on Monday (September 9th) called on Iran to "respond promptly" to the agency's questions regarding Tehran's nuclear programme, AFP reported.
Cornel Feruta was addressing the quarterly board meeting of the International Atomic Energy Agency (IAEA) a day after meeting high-level Iranian officials in Tehran.
He said that in his meetings he "stressed the need for Iran to respond promptly to Agency questions related to the completeness of Iran's safeguards declarations", adding: "Time is of the essence."
Earlier Monday, the IAEA confirmed Iran was installing advanced centrifuges, a move that puts further pressure on the troubled 2015 nuclear deal.
In its statement, the IAEA said the centrifuges had been installed at Iran's Natanz facility and all of them "had been prepared for testing with UF6 (uranium hexafluoride), although none of them were being tested with UF6 on 7 and 8 September 2019".
Iran has also informed the IAEA that it will take steps to accommodate "a cascade of 164 IR-4 centrifuges and a cascade of 164 IR-2m centrifuges".
Under the 2015 Joint Comprehensive Plan of Action (JCPOA), Iran is only meant to enrich uranium using the less advanced IR-1 centrifuge model.
Iran has said it will continue to allow access to IAEA inspectors who monitor its nuclear programme.
Iran has already broken the limits on uranium enrichment levels and the overall stockpile of enriched uranium laid down in the JCPOA.