Iran blocked Telegram, the most popular messaging app in the country, on Tuesday, claiming the service used by 40 million Iranians endangers national security.

It was just the latest in a series of moves by the Iranian authorities to limit use of the app, part of a tug of war between hard-liners and President Hassan Rouhani, who has long campaigned for more freedom on social media.

The hard-liners complain that Telegram poses dangers because Iran’s censors have no control over it. In a statement posted on the news website Mizan, which is associated with the country’s conservative judiciary, a prosecutor accused Telegram of supporting terrorists and other hostile groups.

The minister of information and communication technology, Mohammad Javad Azari Jahromi, at 35 the youngest member of Mr. Rouhani’s cabinet, said on Twitter that trying to stop technology is pointless.

“Administering sanctions against ourselves from the modern world will cause backwardness,” he wrote. (Twitter is also blocked by the Iranian authorities, but it is available to senior officials.)

There have since been reports, so far unverified, that Mr. Azari Jahromi has resigned.

On Tuesday, some users of Telegram in Iran said they were still able to communicate through the app over their home internet connections. In the confusion, several websites that are usually freely accessible — including Wikipedia and Google — were hard to reach.

Iran is not the only country trying to block Telegram. Two weeks ago, Russia obtained a court order to shut down the service after its founder, Pavel V. Durov, refused to provide the security services with the keys to read users’ encrypted messages.

To date, Moscow’s efforts have been thwarted as it continues a cat-and-mouse game with the company, and thousands of Russians demonstratedon Monday in a show of support for Telegram.

In Iran, the battle over the app has become something of a litmus test for Mr. Rouhani, whose popularity has dropped significantly since his re-election in May last year. During his campaign, he promised to deliver more freedoms, to provide greater employment opportunities and to get the country’s notorious morality police off the streets. He has largely fallen short of those goals.

“Mr. President, none of your promises were realized, and preventing Telegram from being blocked is your last stronghold,” a journalist named Nahid Molavi wrote on Twitter.

Telegram is widely used in Iran, for activities as varied as chatting, booking appointments at beauty salons, selling cars or finding partners. Even the supreme leader, Ayatollah Ali Khamenei, had his own channel until recently. Such channels, which sometimes draw hundreds of thousands of users who receive instant messages at the push of a button, played a major role in spreading videos of nationwide protests in December.

On Monday, Iran’s judiciary issued a decree ordering internet service providers to block access to the Telegram app, as they have already been doing for years for Facebook and Twitter.

Many people manage to bypass the state’s firewalls by using virtual private networks, or VPNs. But such software requires a lot of bandwidth, and they often significantly slow internet access.

In recent weeks, government institutions had already begun taking down their Telegram channels, urging people to switch to Iranian applications such as Soroush. But many Iranians chose not to follow the guidance.

Source : www.nytimes.com