The ban that tens of millions of Iranians hoped would never happen appears to have arrived. State television and a news agency affiliated with the Iranian judiciary on April 30 reported that the encrypted Telegram Messenger mobile and desktop messaging app has been blacklisted on the grounds of protecting national security.

Telegram, subscribed to by more than half of Iran’s population of 80mn, has been attacked by both Iran and Russia in recent months, while the UK has warned the secure messaging app is being used by Islamic State militants in Syria. However, it is concerns such as the service’s usefulness when it comes to secretly organising anti-regime demonstrations that is thought to have unnerved Tehran and Moscow, the latter of which has demanded the service’s encryption keys from its co-founder, self-exiled Russian Pavel Durov. Organisers of the nationwide protests that took place in Iran over December and January are known to have used Telegram.

“Considering various complaints against the Telegram social networking app by Iranian citizens and based on the demand of security organizations for confronting the illegal activities of Telegram, the judiciary has banned its usage in Iran,” state television reported. Its report said the Tehran prosecutor was ordering internet service providers to block the cloud-based service in such a way that users would not be able to bypass the ban by using a VPN.

The order was issued one day after the app went down across several time zones on April 29. According to technology experts discussing the matter online, the collapse occurred because the app faced a denial of service attack (DDoS), meaning several million online requests were targeted at the app all at once to jam it.

The Rouhani administration, along with senior Islamic Republic officials, earlier in April advised that the app was set to be blocked although the pragmatist, centrist President Hassan Rouhani cautioned that the move, welcomed by hardliners in the Islamic Republic, might cause a “disruption of the public mood”.

Lately the app has faced several connectivity issues caused by ‘throttling’ as well as the DDoS attack that took the system offline globally. Meanwhile, Iran’s Supreme Leader Ayatollah Ali Khamenei, as well as other senior officials, shut down their official Telegram channels on April 18 in a bid to lobby people to use local messaging app Soroush. Iranian authorities have accused Telegram of allowing its service to be used to spread lies and incite public opinion and spread pornography. They have also claimed that terrorists put the service to use.

Iranian users of messaging services remain unconvinced by local messaging apps, fearing they are the work of their country’s intelligence organisations. Alternative local application Soroush has been ridiculed and slammed by Iranians as insecure and liable to hacking by government agencies. There have been claims it was developed by Iranian intelligence operatives.

One Iranian hacker accessed details of the Iranian telecoms minister, including his mobile phone number, through his unsecured Soroush account and published them on Twitter back to the minister.

“Remove this useless, garbage, insecure, spyware, ugly-looking UI app from play store. Did they give you money, Google? Dear users don't install this app because it's insecure and it has been approved,” the hacker wrote.

The announcement of the blocking of Telegram in Iran coincided with a demonstration involving thousands of Russians in Moscow on April 30. They demanded that the Kremlin remove the ban on the app in their country, which they described as a “national shame”.

Opposition politician Alekei Navalny attended the protest. RFE/RL reported that police briefly stopped Navalny and instructed him to avoid statements or actions that "do not correspond to the agenda of the gathering," held with the permission of the authorities. Navalny reportedly said that police ordered him not to call on the protesters to join another rally scheduled by him for May 5. Navalny responded to the request by sarcastically telling demonstators: "Therefore, I call on you all NOT to take part in the rally on May 5."

On April 16, Russian state media regulator Roskomnadzor started enforcing a court ban on Telegram over its refusal to hand over its encryption keys to the Russian Federal Security Service (FSB).