What did the US cyber-attack do?
The attack had been planned for several weeks, the sources told several US media outlets, and was suggested as a way of responding to the mine attacks on tankers in the Gulf of Oman.
It was aimed at weapons systems used by Iran's Islamic Revolutionary Guard Corps (IRGC), which shot down the US drone last Thursday and which the US says also attacked the tankers.
Both the Washington Post and AP news agency said the cyber-attack had disabled the systems. The New York Times said it was intended to take the systems offline for a period of time.
On Saturday the US Department for Homeland Security warned that Iran was stepping up its own cyber-attacks on the US.
Christopher Krebs, the director of the Cybersecurity and Infrastructure Security Agency, said "malicious cyberactivity" was being directed at US industries and government agencies by "Iranian regime actors and their proxies".
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They were using "destructive 'wiper' attacks", he said, using tactics such as "spear phishing, password spraying and credential stuffing" in a bid to take control of entire networks.
Iran has also been trying to hack US naval ship systems, the Washington Post reported.