Iran’s Transport Ministry website was hit by “cyber disruption” at the weekend, only hours after a similar apparent attack was carried out against the state railway company. The ministry’s website was still inaccessible on Sunday, a day after state television said the computer systems of the staff of the Ministry of Roads and Urban Development were the subject of the attack that resulted in the ministry's portal and sub-portal sites becoming unavailable. It came hours after train services were 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 were affected and that trains ran normally, but Fars news agency reported “unprecedented chaos” at stations with hundreds of trains delayed or cancelled. The Fars report has now been deleted but included photos of station departure boards showing rows of cancelled trips with a message reading “long delays due to cyberattacks”. Telecoms Minister Mohammad Javad Azari-Jahromi gave warning on Saturday of possible ransomware attacks unless vulnerability in computer systems was 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 US and other Western powers have accused Iran of trying to disrupt and break into their networks. Separately, state TV reported that a loud blast heard in north Tehran early on Saturday morning was a stun grenade exploding in a park. The stun grenade – a device which explodes with bright light and a loud sound – had been set up to go off in the park near an adjoining hospital building, a TV reporter said. The report said no one was injured and it is unclear who set it off or why. Tehran Deputy Governor Hamid Reza Goudarzi, who is in charge of security issues, visited the site. “Just one explosion took place inside Mellat [People] Park,” he told the Tasnim news agency. “We are investigating the dimensions and causes of the incident and we will provide information after we are sure.” Attacks are rare in Iran, but a number of sensitive military and nuclear sites have been targeted in recent years. Iran has accused Israel of several attacks on facilities and scientists linked to its nuclear programme. Israel has neither denied nor confirmed the allegations. At the weekend, Iranian government exiles rallied in Berlin and elsewhere to demand the prosecution of the newly elected President Ebrahim Raisi for crimes against humanity. Flag-waving demonstrators rallied at Berlin's Brandenburg Gate and other locations as part of a Free Iran World Summit that featured speeches by former US Secretary of State Mike Pompeo and Slovenian Prime Minister Janez Jansa. In a keynote address, Maryam Rajavi, president-elect of the National Council of Resistance of Iran, accused Mr Raisi of being the “henchman” responsible for the massacre of 30,000 political prisoners in 1988. Iran has never acknowledged the mass executions and Mr Raisi has never publicly addressed allegations about his role. Some clerics say the trials were fair, praising the “eliminating” of armed opposition in the early years of the 1979 Islamic revolution. In an online address, Mr Pompeo described the Iranian presidential election as, “in fact, a boycott and the regime knows it. “This is a show laid bare for the entire world to see,” he said. The council and its largest component, the People's Mujahideen of Iran (MEK), were previously listed as terrorist groups by the US, while the EU categorised the MEK as a banned entity. The US and the EU removed the council and the MEK from the list of banned groups.