British intelligence officials believe that Iran orchestrated a June cyberattack that targeted parliament and breached the email accounts of some 90 government officials, including Prime Minister Theresa May, UK media outlets reported Saturday.
Initially, Russia was suspected to have carried out the attack.
According to intelligence officials, the cyber attack - which was, at the time, scolded as the result of weak passwords - "bombarded" around 9,000 parliamentary email accounts, but only compromised one per cent of the accounts it affected.
According to sources from United Kingdom government, the intelligence officials initially suspected Russian Federation of being responsible for the attack, but now they have come to the conclusion that the attack was launched from Iran, The Telegraph newspaper reported. "The nature of cyber-attacks means it is notoriously hard to attribute an incident to a specific actor".
The attack from Iran shows the nation is stepping up to be one of the world's major cyber powers.
Conservative MP Andrew Bridgen said at the time that such an attack "absolutely" could leave some people open to blackmail.
News of the attack's culprit comes just a day after President Trump announced he would decertify the Iran nuclear deal while stopping short of pulling out of the Obama-era accord.
The U.K. and other European countries involved in the agreement warned the USA on Friday against moves that would harm the Iran nuclear deal, known as the Joint Comprehensive Plan of Action.
May issued a joint statement with German Chancellor Angela Merkel and French President Emmanuel Macron saying they are concerned with "the possible implications" of Trump's decision.
A spokesperson for the National Cyber Security Center, the government body responsible for helping to counter attacks, told the Guardian that: "It would be inappropriate to comment further while inquiries are ongoing".
"We stand committed to the [Joint Comprehensive Plan of Action] and its full implementation by all sides", the three leaders said, adding that preserving the agreement "is in our shared national security interest".
Federica Mogherini, the foreign policy chief of the European Union, said the U.S. can not unilaterally terminate the agreement.