Israel appeared to confirm claims that it was behind a cyber-attack on Iran’s main nuclear facility on Sunday, which Tehran’s nuclear energy chief described as an act of terrorism that warranted a response against its perpetrators. The apparent attack took place hours after officials at the Natanz reactor restarted spinning advanced centrifuges that could speed up the production of enriched uranium, in what had been billed as a pivotal moment in the country’s nuclear programme. As Iranian authorities scrambled to deal with a large-scale blackout at Natanz, which the country’s Atomic Energy Agency acknowledged had damaged the electricity grid at the site, the Israeli defence chief, Aviv Kochavi, said the country’s “operations in the Middle East are not hidden from the eyes of the enemy”. Israel imposed no censorship restrictions on coverage as it had often done after similar previous incidents and the apparent attack was widely covered by Israeli media. Public radio took the unusual step of claiming that the Mossad intelligence agency had played a central role. The unexplained shutdown is thought to be the latest in a series of exchanges between the two arch-enemies, who have fought an extensive and escalating shadow war across the Middle East over more than decade, centred on Iran’s nuclear programme and its involvement in matters beyond its borders. Clashes have more recently been fought in the open, with strikes against shipping, the execution of Iran’s chief nuclear scientist, hundreds of airstrikes against Iranian proxies in Syria, and even a mysterious oil spill in northern Israel, which officials there have claimed was environmental sabotage. Natanz has remained a focal point of Israeli fears, with an explosion damaging a centrifuge assembly plant last July, and a combined CIA and the Mossad cyber-attack using a computer virus called Stuxnet in 2010 that caused widespread disruption and delayed Iran’s nuclear programme for several years. Iran’s nuclear chief, Ali Akbar Salehi, urged the international community and the International Atomic Energy Agency (IAEA) to take action against the perpetrators of the attack. He confirmed that a “terrorist attack” had damaged the electricity grid of the Natanz site. The IAEA said it was aware of the reports but declined to comment further. The developments came as US president Joe Biden prepared to reactivate a bitterly contested deal to offer sanctions relief in return for Tehran limiting its nuclear programme and not pursuing the development of a nuclear weapon. The 2015 pact was the foreign policy centrepiece of Barack Obama’s administration, but was quickly shredded by his successor, Donald Trump, who instead shifted to an aggressive posture to strangle Iran’s economy while bolstering its regional foes. The US defence secretary, Lloyd Austin, arrived in Tel Aviv on Sunday, partly to sell Washington’s new position to sceptical Israeli officials, who fear that even a scaled-back Iranian programme would offer cover for building a nuclear weapon capable of reaching the eastern Mediterranean. After meeting Austin, Israel’s defence minister, Benny Gantz, said: “We will work closely with our American allies to ensure that any new agreement with Iran will secure the vital interests of the world, of the United States, prevent a dangerous arms race in our region, and protect the state of Israel.” The attack on Natanz came five days after an apparent Israeli mine attack on an Iranian freighter in the Red Sea, which western intelligence officials have long claimed was a command and control vessel used to support the Tehran-backed Houthis in the war in Yemen. The cargo ship, known as the Saviz, was seriously damaged by at least one mine, which detonated below the waterline. The ship sent several mayday calls, which were received by the nearby Saudi Arabian coastguard. The strike was the latest in a series of reprisal attacks on shipping from each country on regional waters over several years, much of which has gone unacknowledged. It was followed by a series of Israeli airstrikes in Syria that damaged a military base near Damascus allegedly used by proxies loyal to Iran providing support to the Lebanese militia and political powerhouse, Hezbollah, which remains an essential arm of Iranian foreign policy. Israel last year broke its silence on eight years of airstrikes in Syria, acknowledging that it had been responsible for about 1,000 attacks, which it says were primarily aimed at preventing Hezbollah from fitting advanced guidance systems to rudimentary rockets on Lebanese soil. The Israeli strikes in Syria have caused widespread damage to the country’s military infrastructure, already ravaged by a decade of uprising and war, and have driven diplomatic efforts, led by the United Arab Emirates, to pressure the Syrian president, Bashar al-Assad, to sever an alliance with Iran that has helped him to remain as leader. Despite the urging of several trusted security officials, and the backing of Russia, which has also played a role in securing his regime, Assad has refused the overtures. Hezbollah, which has provided military muscle on behalf of Iran, remains vehemently opposed to such a suggestion, with senior officials fearing that such a repositioning may be aimed at eventually forcing peace talks with its archfoe. Western officials believe Israel has become increasingly brazen in its attempts to disrupt the Iranian programme, pointing to the killing of the country’s leading nuclear scientist, Mohsen Fakhrizadeh, last November, who was shot dead along with his bodyguards on a rural highway. Iran claims that artificial intelligence was used to identify Fakhrizadeh, who was gunned down by a remotely operated automatic weapon. The small lorry carrying the weapon then exploded.