“Basically, going to any website which propagates immoralities and could weaken the religious belief is un-Islamic and not allowed, and membership in it is therefore haram (a sin),” the ayatollah replied.

“Only the use of websites propagating religious criteria and not leading to any kind of ethical immoralities is of no problem,” he added.

According to official figures released last October, 17 million Iranians have a Facebook account, despite heavy restrictions and filtering imposed by the government.