Egyptian photojournalist Mahmoud Abu Zied listens to his trail in a soundproof glass cage inside a makeshift courtroom in Tora prison in Cairo.

An Egyptian court has sentenced 75 people to death, including top figures of the outlawed Muslim Brotherhood group, for their involvement in a 2013 sit-in, state media reports.

On Saturday, the Cairo Criminal Court referred the sentences to the Grand Mufti - the country's top theological authority - for his non-binding opinion as is the norm in capital cases. Though non-binding, the formality gives a window of opportunity for a judge to reverse an initial sentence.

The sentences are subject to appeal.

AMR NABIL/AP Egypt's state-run media says a court has sentenced 75 people to death, including top figures of the outlawed Muslim Brotherhood group, for their involvement in a 2013 sit-in.

Sentencing for more than 660 others involved in the case was scheduled for September 8, the Al-Ahram news website reported. Those sentences, too, are subject to appeal.

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Of the 75 defendants referred to the Mufti, 44 are jailed and 31 are at large. The court normally hands down the maximum sentence for fugitives but a re- retrial is typically held after they are caught.

AMR NABIL/AP Some of the 739 defendants listen to their verdict from a soundproof glass cage inside a makeshift courtroom in Tora prison in Cairo

The case involves a total 739 defendants, including the Muslim Brotherhood's Supreme Guide Mohammed Badie and photojournalist Mahmoud Abu Zeid. The charges range from murder to damaging public property. Neither Badie nor Abu Zeid were sentenced to death in this case.

The 2013 sit-in, in Rabaa al-Adawiya Square in Cairo, supported former Islamist President Mohammed Morsi who was militarily ousted following mass protests against his divisive one-year rule. Morsi hailed from the Brotherhood.

The sit-in was violently dispersed on Aug. 14, 2013. More than 600 people were killed. Months later, Egypt designated the Brotherhood a terrorist organisation.

Egyptian authorities have since launched a severe crackdown on Brotherhood members and supporters, arresting many and trying them on terror-related charges.

Egyptian courts have held mass trials and handed down death sentences for hundreds of people, drawing international condemnation.

In 2014, an Egyptian judge sentenced 529 Morsi supporters to death before 492 were later commuted to life in prison. Death sentences were upheld for the remaining 37.

Rights groups have repeatedly criticised such mass sentencings in Egypt and called on authorities to ensure fair trials.

International rights groups also denounced the mass trial of the 2013 sit-in. Amnesty International described it in a statement last month as a "grotesque parody of justice" and called on authorities to drop all charges against those arrested for protesting peacefully.