"The hired hackers carried out the most extensive attack experienced in Iran's history against the country's infrastructures," Fattahi wrote on his twitter page on Sunday.
He warned that the hackers are after distorting the entire internet in Iran, adding, "The (recent) attack was repelled and the hackers are facing firewalls."
The Iranian internet service suffered hours of disruption on Saturday in what telecoms authorities say was the result of DDoS cyberattack that was dealt with swiftly.
A senior telecoms ministry official said that a “powerful” distributed denial-of-service (DDoS) attack that began 11:54 a.m local Iranian time on Saturday caused users to experience connection issues.
Sajjad Bonabi said that the attack had affected several service providers in Iran, including two notable mobile operators.
He said in a post on Twitter that the DDoS attack was dealt with immediately using the Iranian Information Technology Fortress, known as DEJFA.
“Through an intervention by DEJFA and cooperation of colleagues in Infrastructure Company, the communications are now in a normal condition,” said Bonabi who himself is the deputy head of Iran’s Telecommunication Infrastructure Company.
The official later posted another tweet saying that a last service provider affected by the attacks had reported normal conditions later on Saturday.
Iran has previously reported cyberattacks sponsored by the United States and the Israeli regime that has targeted its key information infrastructure.
DDoS attacks in September targeted Iranian websites that were involved in cryptocurrency trade. Authorities said those attacks were 20 times more powerful than similar attacks in other countries.