CAIRO - An Egyptian court sentenced 183 supporters of the outlawed Muslim Brotherhood to death on Monday on charges of killing police officers, part of a sustained crackdown by authorities on Islamists.

The men were convicted of playing a role in the killings of 16 policemen in the town of Kardasa in August, 2013 during the upheaval that followed the army’s ouster of Islamist president Mohamed Mursi. Thirty-four were sentenced in absentia.

Egypt has mounted one of the biggest crackdowns in its modern history on the Brotherhood since the political demise of Mursi, the country’s first democratically-elected president.

Thousands of Brotherhood supporters have been arrested and put on mass trials in a campaign which human rights groups say shows the government is systematically repressing opponents. President Abdel Fattah al-Sisi, who as army chief toppled Mursi, describes the Brotherhood as a major security threat. The movement says it is committed to peaceful activism.

The death sentences followed one of the bloodiest attacks on Egyptian security forces in years. Islamic State’s Egypt wing claimed responsibility for a series of coordinated operations that killed at least 27 people last week. Sisi blamed the Brotherhood for the violence and told Egyptians in a televised address that the war against militancy will be a long, tough one.

Egyptian authorities make no distinction between the Brotherhood, Islamic State and al Qaeda, arguing that they have a shared ideology and are equally dangerous.

Security forces killed hundreds of Brotherhood supporters and arrested thousands of others after Mursi’s ouster. After the death sentences were read out on Monday, Brotherhood supporters held in metal cages shouted profanities at policemen. A defence lawyer looked at the Islamists and said “You have God.”

The Egyptian government’s human rights record has come under closer scrutiny since woman activist Shaimaa Sabbagh was shot dead during a Cairo protest on January 24, a day before the anniversary of the 2011 uprising that toppled Hosni Mubarak.

The Interior Ministry promised an investigation.

Separately, an Egyptian police officer has been detained on suspicion of killing a suspected member of the Brotherhood in hospital, the Interior Ministry has said.

The suspect was being treated in custody for wounds suffered while he was allegedly planting explosives. The ministry said that the man had provoked the policeman by insulting him. “Then the policeman lost control of his feelings,” it said.  

Meanwhile, Australian journalist Peter Greste on Monday urged Egypt to free his jailed colleagues at Al-Jazeera, describing his “angst” at having to leave them behind after being released. Greste, 49, was arrested for allegedly aiding the blacklisted Muslim Brotherhood, along with colleagues Canadian-Egyptian Mohamed Fahmy and Baher Mohamed of Egypt, in moves that sparked worldwide condemnation.

The award-winning correspondent was freed and deported on Sunday after more than 400 days behind bars in Cairo, and he immediately flew with his brother Michael to Cyprus, where he has been resting before returning to Australia. “This is a massive step forward... I just hope that Egypt keeps going down this path with the others,” Greste told Al-Jazeera in his first interview since leaving prison.

Greste said he felt a “real mix of emotions boiling inside” upon hearing the unexpected news that he was to be released because it meant leaving behind “my brothers” Fahmy and Mohamed. “I went for a run and the prison warden called me over and said: ‘It is time... to get your stuff and go,’” he told the pan-Arab television network. “I feel incredible angst about my colleagues, leaving them behind,” he said. “Amidst all this relief, I still feel a sense of concern. If it’s appropriate for me to be free, it’s right for all of them to be freed.”

Greste said he was overwhelmed by the level of support for the campaign for his release, and that he now looked forward to “watching a few sunsets” and “feeling sand under my toes”. “This has been like a rebirth and you realise that it is those little beautiful moments in life... that’s what’s important.”

Fahmy’s relatives expect him to also be deported under a decree passed by Egypt’s President Abdel Fattah al-Sisi that allows for the transfer of foreigners on trial. His fiancee, Marwa Omara, told AFP in Cairo: “We are expecting Mohamed to be released in the coming days.”

Canada said Greste’s release was “positive” news and that it remained “very hopeful” that Fahmy would also be freed soon. Greste’s family expressed their joy after speaking to him on the phone.

The Australian’s mother, Lois, told a news conference in their hometown of Brisbane: “I’m ecstatic. I just can’t say how happy I am about it.”

His father Juris said it was not clear when he would arrive home. “He is gathering his thoughts for the trip home,” said his brother Andrew. “He is safe, healthy, very, very happy to be on his way home.”

Australian Prime Minister Tony Abbott spoke of his “personal delight and our nation’s relief” at Greste’s release. He also voiced support for a free media and thanked Sisi.

Al-Jazeera vowed to pursue the campaign to free the other two journalists.

But Heather Allan, head of newsgathering at the channel, admitted she wasn’t confident that Mohamed would be released.

“I can’t say I am confident, no. I just don’t know, honestly. Are we going to keep on fighting it? Absolutely - we are not going to leave him there,” she said.

Mohamed’s family has pinned their hopes on a presidential pardon or his acquittal on appeal.

Amnesty International said Greste’s release should not overshadow the ongoing imprisonment of Fahmy and Mohamed.

“All three men are facing trumped up charges and were forced to endure a farcical trial marred by irregularities,” said Amnesty’s Hassiba Hadj Sahraoui.

The European Union described Greste’s release as a “positive step” but called for his colleagues’ to be freed, adding that “journalists must be able to work in a safe working environment”.

The high-profile trial, at which Greste and Fahmy were sentenced to seven years in prison and Mohamed to 10, proved a public relations nightmare for Sisi, who has cracked down on Islamists since toppling president Mohamed Morsi in July 2013.

The verdict was overturned and a court in January ordered a retrial for the three.

Egyptian police arrested the journalists at the peak of a diplomatic row between Cairo and Qatar, which owns Al-Jazeera.

The broadcaster had been critical of the deadly crackdown on Morsi’s Muslim Brotherhood following the Islamist leader’s overthrow.

Qatar has since moved to mend ties with Egypt, and Al-Jazeera has closed its Arabic-language Egyptian affiliate which backed the Brotherhood.

The rapprochement reflected growing international acceptance of the crackdown on Egypt’s Islamist opposition and militants who have killed scores of police and soldiers since Morsi’s overthrow.

The crackdown, which has left at least 1,400 people dead, had tested Egypt’s ties with the United States, which temporarily froze part of its annual $1.3 billion military aid in 2013.

Greste worked for multiple news organisations before joining Al-Jazeera English. He was the BBC’s Kabul correspondent in 1995 and returned there after the US-led invasion in 2001. From 2009, he was based in Nairobi, winning the broadcasting industry’s prestigious Peabody Award in 2011.