The US and Iran war has now entered the cyber world with the US covertly launching a cyber-attack against an Iranian intelligence group's computer systems.

The cyber-attack, which were approved by US President Donald Trump on Thursday, targeted computer systems used to control missile and rocket launches that were chosen months ago for potential disruption, a US official familiar with the matter said on Saturday.

The strikes were carried out by US Cyber Command and in coordination with US Central Command, reports Efe news.

The attack came during the peak of tensions this week between the US and Iran over a series of incidents across the Middle East, including Tehran's shooting down of an American reconnaissance drone.

It also came as US fears have grown that Iran may seek to lash out with cyber-attacks of its own, as multiple cybersecurity firms said they had already seen signs Tehran is targeting relevant computer networks for intrusion and appeared particularly focused on the US government and the American energy sector, including oil and gas providers.