"The Americans have repeatedly threatened and mounted cyber-attacks against us," Jalali said today.
"The legal implications of such actions could naturally affect them and Iran is seriously following up the issue at its juridical and foreign ministry capacities," he said, adding that Iran is putting in place robust security measures to protect its vital infrastructure.
Last month, US media reports said the United States was considering possible cyber-attacks against Iran after the September 14 attacks on Saudi oil sites which Washington was quick to blame on Iran without evidence.
Jalali said, "Our task is to enhance our cyber defense preparations in the energy and other critical areas."
The official said his office has been upgrading its preparations through special drills held periodically, in which emergency response teams identify and fix weaknesses and security holes in simulated cyber-attacks.
"In the last six months, we have had almost 120 drills and tests, about 70% of which were in the energy field, controlling all refinery, petrochemical, gas, transfer, central and control systems and resolving almost all weaknesses," Jalali said.
"Our enemies consider the cyber domain as one of the main areas of threat against nations, especially Iran," Jalali said then, calling for security at industrial installations to be beefed up.
Last month, Iranian Foreign Minister Mohammad Javad Zarif lashed out at Washington for launching a cyber-attack against nuclear facilities in his country, reprimanding the White House for irresponsibly ignoring the fact that the attack could have claimed millions of civilians lives.
In an interview with NBC's "Meet The Press," Zarif referred to Stuxnet, a malicious computer worm that is widely believed to be have been made by the US and Israel.
"There is a cyber-war going on. The United States started that cyber war, with attacking our nuclear facilities in a very dangerous, irresponsible way that could've killed millions of people," he said.
"There is a cyber-war and Iran is engaged in that cyber war," he added. "Any war that the United States starts, it won't be able to finish."
Asked whether Iran was attempting to interfere with the 2020 US presidential election, Zarif said the Islamic Republic doesn't have a preference in the race.
"We don't have a preference in your election to intervene in that election," he said. "We don't interfere in the internal affairs of another country."
The Washington Post reported in June 2012 that the US National Security Agency (NSA), its spy service CIA, and Israel’s military had worked together to launch Stuxnet against Iran’s nuclear facilities.
In late 2015, Iran's then Foreign Ministry Spokesman, Hossein Jaberi-Ansari, called the attacks that came in 2007 "illegal," saying Tehran had never responded with "reciprocal cyber-attacks".
In November 2016, Head of the Atomic Energy Organization of Iran (AEOI), Ali Akbar Salehi said the cyber-attack had worked against the US and Israel’s intended objectives and instead helped improve the Islamic Republic’s readiness against such acts of sabotage.
The deployment of the malware against Iran’s nuclear facilities had made the country realize how it had to prepare against such attempts, Salehi said at the time.
This May, Minister of Information and Communications Technology Mohammad Javad Azari Jahromi announced that Iran has developed an indigenous firewall securing its sensitive industrial facilities against Stuxnet.