Iran has installed extra advanced centrifuges at its underground uranium enrichment plant at Natanz that was hit by a blast last week, a report by the U.N. atomic watchdog on Wednesday showed, deepening Iran"s breaches of its nuclear deal with major powers. The explosion and a power outage damaged an unknown number of centrifuges and Iranian state TV has shown footage of machines that it says were replaced there. Iran has blamed Israel for the explosion. Israel has not commented formally on it. The International Atomic Energy Agency report was not clear on how many centrifuges are in use but it gave "up to" numbers of advanced machines installed at the plant that were higher than previously indicated. The report made no mention of the explosion or its effect on the plant"s activity. "On 21 April 2021, the Agency verified at FEP that: ... six cascades of up to 1,044 IR-2m centrifuges; and two cascades of up to 348 IR-4 centrifuges ... were installed, of which a number were being used," the IAEA report to member states said, referring to the underground Fuel Enrichment Plant at Natanz. The report was seen by Reuters. According to a previous report, the IAEA verified on March 31 that Iran was using 696 IR-2m machines and 174 IR-4 machines at the FEP. Wednesday"s report is the latest evidence that Iran is pressing ahead with the installation of the advanced machines, even though it is not allowed to use them to produce enriched uranium under the 2015 agreement. The accord only lets Iran produce enriched uranium at its underground Fuel Enrichment Plant (FEP) at Natanz with first-generation IR-1 centrifuges, which are far less efficient than the advanced models. Wednesday"s report also said Iran informed the IAEA that it plans to install four more cascades, or clusters, of IR-4 centrifuges at the FEP, where both of the IR-4 cascades it had planned have now been installed. European parties to the agreement have seen progress in the first two rounds of indirect U.S.-Iran negotiations to revive the deal but said on Wednesday that there were still major hurdles to overcome. read more The United States withdrew from the accord in 2018 and re-imposed sanctions on Iran under President Donald Trump, who objected to the deal and sought to wreck it. Iran responded as of 2019 by breaching many of the deal"s restrictions on its nuclear activities.