HAYDEN COOPER, PRESENTER: A dangerous game of political brinkmanship is escalating in the Middle East as the region's two superpowers abandon diplomatic links. Sunni Saudi Arabia and Shiite Iran are trading strong words and expelling diplomats after Saudi authorities executed an influential Shiite cleric. It led to a violent demonstration at the Saudi embassy in Tehran and then the cutting of diplomatic ties by Riyadh. For two countries already fighting on opposing sides in Syria and Yemen, it's a major blow to any chance of peace.

Dr Mohammad Marandi is Dean of the World Studies Faculty at the University of Tehran. He joined me from the Iranian capital a short time ago.

Dr Marandi, thanks for joining us. The Iranian authorities have threatened divine revenge for this execution. What exactly does that mean?

MOHAMMAD MARANDI, DEAN OF WORLD STUDIES, UNIVERSITY OF TEHRAN: Well the Iranians, being a religious people, believe that the Saudis will not get away unscathed. The Saudis, after all, have been promoting this extremism across the board, and ultimately, the chickens will come home to roost. The Iranians believe that the United States is also making a grave mistake by siding with the Saudis in Syria. The Saudis we know have been supporting extremism for years. The former US General Flynn, who was the head of the Defense Intelligence Agency of the Pentagon during 2012 to 2014, said that American allies in the region were supporting the extremists and that the United States supported its allies. So the Iranians believe that the United States is going to face blowback and the Saudis will face blowback for these policies.

HAYDEN COOPER: What about the extremism that is being backed by Iran all across the region? The Iranians are supporting a rebel group in Yemen that wants to overthrow the Government. They're backing Hezbollah in Lebanon and Syria. They're supporting the Assad regime which carries out untold atrocities on the Syrian people. Are you really trying to suggest that the Iranians are a good neighbour in the Middle East?

MOHAMMAD MARANDI: Yes, I do believe that the Iranians are a good neighbour. The Iranians have supported the people of Yemen. The Saudis are bombing as we speak the capital of Yemen. They've been doing it for 10 months. They are invading a neighbouring country. The Iranians support the government that is in the capital and has been in the capital. On the other hand, Hezbollah is a group that is recognised by the Lebanese Government. It has members of Parliament and it has two members in the cabinet. So when the Lebanese Government accepts the legitimacy of Hezbollah, which has basically been a resistance organisation that expelled Israel from southern Lebanon, then there's no reason why anyone else should call it a terrorist organisation. And in Syria, the Iranians believe that they've actually made the right call. From the beginning, the Iranians called for reform in Syria, but the Iranians from the very beginning were saying that the Saudis, the Turks and the Qataris were supporting extremism. Back then, Western governments and Western news agencies were silent, but now we - just last year, the revelation by General Flynn, the former head of the Defence Intelligence Agency, I think was the revelation of the year and they basically admitted that this is exactly what happened and the Americans knew this.

HAYDEN COOPER: Alright. I want to talk very briefly about this sheik who has started the latest escalation. What sort of a person was he? How significant a figure is he in Iran, given that he doesn't live there? And was he, as the Saudis suggest, basically an Iranian agent inside Saudi Arabia?

MOHAMMAD MARANDI: Well this gentleman basically was peaceful. He had no weapons. He never called for any military uprising. He basically said that Wahhabism and Saudi extremism is - is sectarian and that it is unacceptable. That is basically what he has been calling for. I'd like to also compare him to someone that both the United States Government and the Saudis have regretted that person's death and that is Zahran Alloush, the head of a terrorist group in Syria who was killed a couple of weeks ago called - and he called for the death of minorities in Syria. He supported Osama bin Laden as well as being an ally of al-Qaeda in Syria. And this person, that both the Americans and the Saudis regretted his death and he was the head of a major terrorist organisation in southern Syria. So when you compare the regret expressed by the Saudis for a sectarian killer in Syria, and - on the one hand, and you look at this gentleman, who was arrested for leading protests and then executed for no reason whatsoever, I think that reveals a lot about Saudi Arabia.

HAYDEN COOPER: Could the Iranian authorities have done a better job of controlling the protest at the Saudi embassy in Tehran?

MOHAMMAD MARANDI: Yes, I think that the protests at the embassy should've been better managed by the security forces in Tehran. Of course there is a great deal of anger directed at Saudi Arabia in Iran because of its sectarianism, because of the death of many Iranians during the pilgrimage a few months ago and the other grievances that Iranians have. But without a doubt, the Government should've done a better job. But 38 people have been arrested subsequent to the - the protests.

HAYDEN COOPER: And just finally and briefly, Dr Marandi, we often hear politicians here and across the globe urging a political solution to the war in Syria, but that would require Iran and Saudi Arabia actually agreeing on something, wouldn't it? That seems very unlikely at the moment.

MOHAMMAD MARANDI: Well I think the real question is: is the current President in Syria better or is Wahhabi extremism better? Is al-Qaeda better or is the current administration in Syria better? The Iranians, from the very beginning, they made a moral choice, despite the severe shortcomings that the Syrian Government has, the Iranians believe that the alternative that was being supported by Saudi Arabia, which included al-Qaeda - back then of course, ISIL was al-Qaeda in Iraq and then they broke away. But whether it's al-Qaeda or ISIL or Jaysh al-Islam, which was led by Zahran Alloush, who was killed a couple of weeks ago, all of these are extremist organisations that will threaten Europe and the rest of the region and our region and the international community. So the Iranians believe that these extremists must be stopped and Saudi Arabia must stop promoting Wahhabi extremism, both at the ideological level and they must stop supporting the militants, otherwise the terrorism will even reach Australia and Muslims cannot be blamed for this, neither Sunni or Shia, because Wahhabism is a school of thought of its own.

HAYDEN COOPER: Dr Marandi, thank you very much for joining us tonight.

MOHAMMAD MARANDI: Thank you for having me.