Iran insists its nuclear program is peaceful and was enraged by the EU’s decision in January to impose a boycott on its oil. It responded by threatening to close the Strait of Hormuz (pictured), the primary Gulf oil shipping lane.

Iran’s oil ministry has called a crisis meeting after a malware attack late on Sunday forced it to disconnect key oil facilities.

The ministry and national oil company’s main websites and internal communications systems were infected by the virus, as were the computer and communications systems of Iran’s main oil export facilities on Kharg Island, which exports 80 percent of the country’s daily 2.2 million barrels, The Guardian reports.

Terminals on the islands of Gheshm and Kish were also hit. Computer systems controlling the oil facilities have been disconnected from the Internet as a precaution, while deputy oil minister in charge of civil defence Hamdollah Mohammadnejad said: “We are making plans to neutralise this cyber-attack.”

Oil production was not affected by the virus, the semi-official Mehr news agency reported, but the website of Iran’s national oil company remained unreachable for much of Monday.

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A spokesperson for the oil ministry was quoted as saying that data about users of the websites had been stolen in the attack, according to the BBC. Mohammadnejad said that Iranian authorities had established a crisis unit in the wake of the attack to bolster defences, Reuters reports.

Sunday’s attack is reminiscent of the Stuxnet computer virus which struck Iran’s nuclear program in 2010. Suspicion over that attack has focused on the US, possibly with the assistance of the US, the Agence France Presse reports

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