Experts note the blackout is unprecedented in its extent but also selective, allowing some government communications

Iran’s internet shutdown, now in place for 36 hours as the authorities seek to quell escalating anti-government protests, represents a “new high-water mark” in terms of its sophistication and severity, say experts – and could last a long time.

As the blackout kicked in, 90% of internet traffic to Iran evaporated. International calls to the country appeared blocked and domestic mobile phones had no service, said Amir Rashidi, an Iranian digital rights expert.