The cyber-attack on the heavily guarded Natanz plant in Iran will set back Tehran’s nuclear programme by nine months, US intelligence sources have claimed. Iran’s foreign ministry has blamed Israel for sabotaging Iran’s main uranium enrichment facility, and although Israel has not formally confirmed responsibility its officials have done little to dispel the notion. US intelligence sources told the New York Times Saturday’s attack led to an explosion that destroyed the independently protected power supply to advanced centrifuges that create enriched uranium, and that it could take at least nine months to restore production. The sources said they believed Israel was responsible. Israeli media quoted intelligence sources as saying the Mossad spy service carried out a successful cyber-sabotage operation. Iran said not all the centrifuges had been damaged and some production could restart next week. Iranian intelligence claimed to have identified an individual inside the plant’s hall who was responsible for the sabotage by disrupting the flow of electricity, but the account was being treated with caution and may be intended to show the plant was not vulnerable to an external cyber-attack. At a press conference, the Iranian foreign ministry said no one was injured and only a relatively simple centrifuge had been damaged, which would be replaced by more advanced models that could purify uranium at greater speed. However, the plant’s proven vulnerability to Israeli attack makes this claim questionable. The White House press spokesperson said the US said had seen the reports about the incident, adding that “the US was not involved in any manner”. There was no comment on the attack by the US defence secretary, Lloyd Austin, who was in Jerusalem at the time. Standing next to him at a press conference, Israel’s prime minister, Benjamin Netanyahu, did not confirm his country’s role in the attack but appeared to reference the incident. “My policy as prime minister of Israel is clear – I will never allow Iran to obtain the nuclear capability to carry out its genocidal goal of eliminating Israel,” he said. France, Britain and Germany are in the middle of highly sensitive talks with Iran in Vienna on the terms for the US and Iran to return to full compliance with the 2015 nuclear deal constraining Iran’s nuclear programme. Israel is vehemently opposed to the talks and has always argued it had a right to attack Iran to protect itself. No immediate comment came from France or Britain, but the German foreign minister, Heiko Maas, appeared to condemn the attack. “What we are hearing currently out of Tehran is not a positive contribution, particularly the development in Natanz,” he told a press conference. Peter Stano, a spokesperson for the EU, said the bloc rejected any attempts to undermine or weaken diplomatic efforts on the nuclear agreement, but that “we still need to clarify the facts” about what took place at Natanz. The EU also imposed further sanctions on eight Iranian officials for human rights abuses. In a discussion on Monday with Iranian security officials, the country’s foreign minister, Javad Zarif, said of Israel: “The Zionists want to take revenge because of our progress in the way to lift sanctions … they have publicly said that they will not allow this. But we will take our revenge from the Zionists. “If they think our hand in the negotiations has been weakened, actually this cowardly act will strengthen our position in the talks.” He said more advanced centrifuges would be installed at Natanz to replace those that had been damaged. Some Iranian parliamentarians, including the deputy speaker, Amir-Hossein Ghazizadeh Hashemi, urged Iran to suspend talks set for Wednesday until Israel was punished for the attack. The White House said it had received no reports that the talks were going to be delayed. Iran had initially given a low-key response to the attack, saying it was investigating an accident, but through Sunday and Monday it became more explicit that its nuclear programme had been attacked in an act of terrorism that could have caused a catastrophe and needed to be condemned. The Natanz uranium enrichment site, much of which is underground, is one of several Iranian facilities monitored by inspectors of the International Atomic Energy Agency (IAEA), the UN nuclear watchdog. Israel’s apparent intervention came at a delicate time in the negotiations as Iran decides if it is willing to open direct talks with the US, or instead, as last week, continue to work through European intermediaries. The two sides are in the middle of negotiating whether the US must lift all sanctions imposed after 2016 or a selective group linked to the nuclear deal. Iran has said it will only return to compliance with its side of the deal after the US lifts all the required sanctions that have throttled its economy. Iranian negotiators have claimed as many as 1,600 different sanctions must be lifted. The US says some of these are not related to the enforcement of the nuclear deal but to terrorism, human rights, Iran’s missile programme or money laundering.