As protests spread across Iran, there is one man who has been fanning the flames of dissent from overseas using an anonymous messaging app.

Meet Roohollah Zam, an exiled journalist and former government policy adviser who has been using channels on Telegram to plan protests and share videos of unrest.

Zam was sharing the videos through the channel of his news network, AmadNews, before it was shut down by the government.

But that only prompted him to set up a multitude of other channels before the whole app, used by an estimated 40million people in Iran, was cut off by the regime.

Roohollah Zam, an exiled Iranian journalist, has been using his news channel on app Telegram to help organise protests and spread news of the marches

Iran 'temporarily' blocked all access to the app on Sunday, along with Instagram, saying it was imperative to restore public order

Iran has accused Zam of inciting violence, allegations he denies, and said the move was necessary to restore public order.

It's hard to overstate the power of Telegram in Iran. Of its 80 million people, around half use the free app created by Russian national Pavel Durov.

Its clients share videos and photos, subscribing to groups where everyone from politicians to poets broadcast to fellow users.

While authorities ban social media websites like Facebook and Twitter and censor others, Telegram users can say nearly anything. In the last presidential election, the app played a big role in motivating turnout and spreading political screeds.

Telegram touts itself as being highly encrypted and allows users to set their messages to 'self-destruct' after a certain period, making it a favorite among activists and others concerned about their privacy. That too has made it a worry of Iranian authorities.

Zam has used the app to share news and information published by his AmadNews website. Posts included times and locations for protests, as well as videos of demonstrators shouting inflammatory chants, including those targeting Supreme Leader Ayatollah Ali Khamenei and President Hassan Rouhani, a relative moderate in Iran's clerically overseen government.

Thousands have taken to the streets of several cities over the past three days to vent anger at high unemployment and rising prices, in the largest demonstrations since those that followed a disputed election nine years ago.

Officials have meanwhile targeted Telegram in recent remarks, with prosecutors going as far as filing criminal charges against Durov.

Protesters gathered in Tehran on Sunday as Iran was engulfed by a fourth straight night of demonstrations against the regime

The marches started in second city Mashhad last week before spreading across the country (pictured, protesters tear down a barrier in Tehran)

Tear gas and water cannons were used to disperse activists who gathered in Tehran overnight

On Saturday, Iran's Telecommunications Minister Mohammad Javad Azari Jahromi wrote to Durov on Twitter, complaining AmadNews was 'encouraging hateful conduct, use (of) Molotov cocktails, armed uprising and social unrest.'

Durov responded by saying Telegram suspended the account.

'A Telegram channel (Amadnews) started to instruct their subscribers to use Molotov cocktails against police and got suspended due to our 'no calls for violence' rule. Be careful - there are lines one shouldn't cross.' Durov tweeted.

Zam, who has said he fled Iran after being falsely accused of working with foreign intelligence services, denied inciting violence on Telegram.

Telegram's decision drew criticism from free internet advocates and Iranians. Edward Snowden, the former National Security Agency contractor who exposed U.S. government surveillance programs in 2013, said Telegram should instead be working on how to make the service accessible after a potential government ban.

'Telegram will face increasing pressure over time to collaborate with the Iranian government's demands for this or that,' Snowden wrote on Twitter. He added: 'You can't keep an independent, destabilizing service from being blocked in authoritarian regimes, you can only delay it.'

Telegram was co-founded by Russian Pavel Durov and is known for its tough encryption which keeps messages hidden from security services and the government

Those words proved prophetic Sunday, as Durov himself wrote on Twitter that Iran blocked the app 'for the majority of Iranians after our public refusal to shut down ... peacefully protesting channels.' Iranian state television later quoted an anonymous official as saying the app would be temporarily limited as a safety measure.

It also marks a setback for Zam, the son of Shiite cleric Mohammad Ali Zam, a reformist who once served in a government policy position in the early 1980s.

The cleric wrote a letter published by Iranian media in July in which he said he wouldn't support his son over AmadNews' reporting and messages on its Telegram channel.

'I found that you crossed the red line,' the cleric wrote, referring to comments the channel circulated about Supreme Leader Ayatollah Ali Khamenei. 'Our red line is the supreme leader, but you passed the red line.'

Zam did not respond to a request for comment Sunday from The Associated Press, though he published a video late Saturday on the channel being blocked.

'Unfortunately the Amadnews was blocked,' Zam said in a message to his followers. A new channel 'will continue its work as hard as before and with the help of God, we will become millions again.'

At least 1.7 million people have viewed the first message on the new channel, according to Telegram. It called for protests Sunday at sites across Iran before the government ordered the app shut down.