The head of the Guardian Council, one of Iran’s most powerful institutions, has declared that detained opposition leaders “should be executed” like the former Italian Fascist leader Benito Mussolini.

Ayatollah Ahmad Jannati (pictured) issued the declaration in a prime-time interview on Iran’s main State TV channel, IRIB 1.

Arguments over the fate of Mir Hossein Mousavi, Mehdi Karroubi, and Zahra Rahnavard — held under strict house arrest since February 2011 — have escalated in recent weeks. Prominent MP Ali Motahari has challenged President Rouhani to fulfil his campaign promise to free the three leaders. Clerics such as Grand Ayatollah Yusuf San’ei and Seyed Hadi Khamenei, the brother of the Supreme Leader, have offered public support.

Last week, the conference of Karroubi’s Etemade Melli Party, joined by other reformists such as former President Mohammad Khatami, issued a call for the release of Karroubi and Mousavi — both candidates in the disputed 2009 Presidential election — and Mousavi’s wife Rahnavard, a leading artist, activist, and academic.

Jannati hit back in his interview:

Those who want freedom of the leaders of the Sedition have neither political intrigue nor believe in the Revolution or the Supreme Leader….

The system has been kind to them; as if they were tried a just and intelligent judge would have issued no other sentence but a death sentence for them….They should be executed without a trial like Mussolini was.

Jannati’s assertion revived memories of a demand by MPs for the execution of Mousavi and Karroubi, just before confirmation of their house arrest in February 2011:

The Supreme Leader said recently that the house arrest proved the humanity of the Islamic Republic in dealing with the “sedition” of the opposition leaders, saying the detention would have been ordered by the late Ayatollah Khomeini.

Immediately after Jannati’s interview, Motahari wrote the head of the Guardian Council:

Why are you so afraid of a trial? Is it because that you are worried that some facts will be known and the propaganda you have carried over these years become worthless and meaningless?

You have given them a death sentence without hearing their defence. Doesn’t this bring your justice under question and doesn’t it undermine your position in the Guardian Council?

Now that they insist on a trial, why you don’t hold one? Why are you more interested in house arrest which has no legal or moral justification and is against many principles of the constitution?

And the MP is far from alone in his response, featured by the outlet of Speaker of Parliament Ali Larijani, Khabar Online.

Larijani’s brother-in-law, Ayatollah Mustafa Mohaqegh Damad, issued a public letter expressing his disappointment over the interview as “the cause of disrespect toward Islamic Jurisprudence and judgement”.