The website of Iran's transport ministry was taken down on Saturday by what state television said was a "cyber disruption," a day after an apparent cyberattack on the state railway company.
Computer systems of the staff of the Ministry of Roads and Urban Development were the subject of the attack which resulted in the ministry's portal and sub-portal sites becoming unavailable, the TV channel reported.
It didn't give any indication of who it believed could have been behind the attack and did not say if any ransom demand had been made.
Train services had been disrupted on Friday, with hackers posting fake delay notices on station boards, state-affiliated news outlets reported. The government-run railway company said only the displays had been affected and that trains ran normally.
Telecommunications Minister Mohammad Javad Azari-Jahromi warned on Saturday of possible ransomware attacks unless vulnerabilities in computer systems were dealt with, Iranian news outlets reported.
In late 2020, Iran said hackers launched large-scale attacks on two of its government institutions, without giving details on the targets or the suspected perpetrators.
Iran says it is on high alert for online assaults, which it has blamed in the past on the United States and Israel. The United States and other Western powers meanwhile have accused Iran of trying to disrupt and break into their networks.