VIENNA, Sept 27 (Reuters) - Iran must stop denying the U.N. nuclear watchdog access to a workshop making centrifuge parts as agreed two weeks ago or face diplomatic retaliation at the agency"s Board of Governors within days, the United States said on Monday. The workshop at the TESA Karaj complex makes components for centrifuges, machines that enrich uranium, and was hit by apparent sabotage in June in which one of four International Atomic Energy Agency cameras there was destroyed. Iran removed them and the destroyed camera"s footage is missing. TESA Karaj was one of several sites to which Iran agreed to grant IAEA inspectors access to service IAEA monitoring equipment and replace memory cards just as they were due to fill up with data such as camera footage. The Sept. 12 accord helped avoid a diplomatic escalation between Iran and the West. "We are deeply troubled by Iran"s refusal to provide the IAEA with the needed access to service its monitoring equipment, as was agreed in the September 12 Joint Statement between the IAEA and Iran," a U.S. statement to the IAEA"s 35-nation Board of Governors on Monday said. It was responding to an IAEA report to member states on Sunday that said Iran had granted access to sites as agreed on Sept. 12 but not to the workshop, where IAEA inspectors were denied access on Sunday. They had planned to check if the workshop was ready to operate and re-install cameras if it was. Iran"s envoy to the IAEA, Kazem Gharibabadi, said overnight on Twitter that before the deal with the IAEA, Iran indicated that monitoring equipment at Karaj was "not included for servicing" because of ongoing investigations and Sunday"s report "goes beyond the agreed terms of the JS (Joint Statement)". "WITHOUT FURTHER DELAY" The European Union told the IAEA board that Iran"s failure to grant the IAEA access to the workshop was "a worrying development, contrary to the Joint Statement reached on 12 September 2021." A resolution criticising Iran at the Board of Governors could kill hopes of resuming indirect talks between Iran and the United States to bring both sides back into compliance with the 2015 Iran nuclear deal. Iran usually bristles at such resolutions and its news hardline President Ebrahim Raisi has said Iran is prepared to return to the negotiating table but not under Western "pressure". Iranian Foreign Minister Hossein Amirabdollahian said on Friday Iran would return to the talks "very soon". read more "We call on Iran to provide the IAEA with needed access without further delay," the U.S. statement said. "If Iran fails to do so, we will be closely consulting with other board members in the coming days on an appropriate response." read more The European Union also called on Iran to grant access "without any further delay".