The move came just weeks after Iran’s rulers started telling people to instead use locally-developed communications platforms.

“Considering various complaints against the Telegram social networking app by Iranian citizens, and based on the demand of security organizations to confront the illegal activities of Telegram, the judiciary has banned its usage in Iran,” Reuters quoted state TV as saying.

The Iranian judiciary said it had banned Telegram because of “propaganda against the establishment, terrorist activities, spreading lies to incite public opinion, anti-government protests and pornography.”

Iran has previously issued temporary blocks on Telegram during waves of protests, such as those that took place at the end of last year and in January this year. At the time, Telegram founder Pavel Durov said the platform had refused to shut down channels used for peaceful protests—Telegram channels are public groups, separate from the encrypted-functionality that the app also provides.

Telegram is hugely popular in Iran. According to Al Arabiya, 40 million people there—around half the population—use it.

Both President Hassan Rouhani and Ayatollah Ali Khamenei, Iran’s supreme leader, announced in April that they would no longer use the platform. Khamenei did so while urging followers of his Telegram channel to instead use homegrown platforms such as Soroush and Gap.

It remains to be seen how well the ban will work in practice. As in Iran, Russian authorities have also ordered Internet service providers to block access to Telegram, but it reportedly still works there.

Indeed, the Russian Telegram ban—which stems from Telegram’s refusal to hand over the keys to users’ encrypted conversations—has proved to be a debacle.

In order to keep Telegram up and running in the country, the app’s developers moved its backend infrastructure over to a series of cloud platforms, such as those run by Amazon and Google. The Russian telecommunications regulator, Roskomnadzor, responded by adding millions of those cloud platforms’ IP addresses to its blacklist, taking out bystander web services that also rely on the platforms.

Thank you, each and one of the 12,000+ people who stood up to support the freedom of internet and Telegram today in central Moscow. You make me proud and excited to be Russian. https://t.co/1Vwa1FQgIO

— Pavel Durov (@durov) April 30, 2018

Durov, a veteran entrepreneur who these days lives outside Russia, is organizing protests against the ban.