CAIRO (AP) — An Egyptian court on Monday sentenced to death 529 supporters of ousted Islamist President Mohammed Morsi in connection to an attack on a police station that killed a policeman, convicting them after only two sessions in a mass trial that raised an outcry from rights activists.

The verdicts are subject to appeal and would likely be overturned, rights lawyers said. But they said the swiftness and harshness of the rulings on such a large scale deepened concerns that Egypt's courts have been politicized and that due process is being swept away amid a monthslong crackdown on Morsi's Muslim Brotherhood supporters since the military removed the president last summer.

Egyptian authorities are holding a series of mass trials of Morsi supporters, with anywhere from dozens to hundreds of defendants at a time that have already raised worries among rights observers. Monday's verdicts by a court in the city of Minya, south of Cairo, were the first such mass trial to issue death sentences.

The court held two sessions. In the first on Saturday, the judge angrily shouted down requests by defense lawyers for more time to review the prosecution's case for the hundreds of defendants. In Monday's session, security forces barred defense lawyers from entering the courtroom on orders from the judge, the provincial police chief said.

"We didn't have the chance to say a word or to look at more than 3,000 pages of investigation to see what evidence they are talking about," Khaled el-Koumi, a lawyer representing 10 of the defendants, told The Associated Press.

All but around 150 of the defendants in the case were tried in absentia. The judges acquitted 16 defendants.

The 545 defendants in the case were charged with murder, attempted murder and stealing government weapons in connection with an attack on a police station in August in the town of Matay in Minya province. One police officer was killed in the attack. The violence was part of rioting by Islamists around the country, sparked when security forces stormed two pro-Morsi sit-ins in Cairo, killing hundreds of people on Aug. 14.

After the verdict was announced, families of the defendants protested outside the court building in Minya, shouting, "We will not be silenced" and "down with military rule." Police arrested three people from the protest. Fears of a backlash by Morsi supporters prompted security officials to go on alert around Minya province.

Mohammed Zarie, a Cair-based human rights lawyer who was not involved in the case, said the verdicts reflect has Egypt's judiciary is turning "from a tool for achieving justice to an instrument for taking revenge."

"This is way over the top and unacceptable," he said. "This verdict could be a precedent both in the history of Egyptian courts and perhaps, tribunals elsewhere in the world."

The offices of the interim president and prime minister did not immediately respond to requests for comment on the verdict.

During the first session on Saturday, defense lawyers asked the presiding judge, Said Youssef, to postpone the case to give them time to review the hundreds of documents in the case, but the request was declined, el-Koumi said. When the lawyers protested, Youssef shouted that they would not dictate what he should do and ordered court security to step in between him and the lawyers.

A security official in the courtroom said the defendants and the lawyers disrupted the proceedings by chanting against the judge: "God is our only refuge!" He spoke on condition of anonymity because he was not authorized to speak to the press.

"The judge stood up, looked at us, put his hands on his belly and announced: Monday is the verdict," another defense lawyer, Yasser Zidan said.

On Monday, police and special forces beefed up security around the court ahead of the session, encircling the building and blocked its doors with a bench to prevent lawyers from entering, said Zidan, who was among the lawyers turned away.

Minya's provincial police chief Osama Metwali told AP that the judge ordered the measures because of "disruptions" during the previous session.

"This is a black day in the history of courts and in the world," Zidan said. " I know that the court of appeals will overturn the verdict but what I am crying about is the downfall of the justice in Egypt today."

A senior Brotherhood figure, Ibrahim Moneir, denounced the verdicts, warning that abuses of justice will fuel a backlash against the military-backed government that replaced Morsi.

"Now the coup is hanging itself by these void measures," he said, speaking to the Qatari-based Al-Jazeera Mubashir Misr TV station.

On Tuesday, another mass trial against Morsi's supporters opens in a Minya court with 683 suspects facing similar charges. The defendants in that case include Brotherhood leader Mohammed Badie, who also faces multiple other trials, and senior members of the group from Minya province.

Egypt's military toppled Morsi in July after four days of massive demonstrations by his opponents demanding he step down for abusing power during his year in office. Since then, Morsi's Brotherhood and other Islamist supporters have staged near-daily demonstrations that usually descend into violent street confrontations with security forces.

The military-backed government has arrested some 16,000 people in the ensuing crackdown, including most of the Brotherhood leadership.

At the same time, militant bombings, suicide attacks and other assaults — mostly by an al-Qaida-inspired group — have increased, targeting police and military forces in retaliation for the crackdown. The authorities have blamed the Brotherhood for the violence, branding it a terrorist organization and confiscating its assets. The group has denied any links to the attacks and has denounced the violence.

The massive sweeps have already raised concerns over due process. Rights lawyers have complained that courts and prosecutors tend to side with police in cases — while ignoring police abuses. Notably, last week, another court gave light sentences to four policemen convicted in the deaths of more than 30 detainees protesters who suffocated inside a police truck during the August crackdown.

With authorities casting the arrests of Brotherhood supporters as part of a fight against terrorism, however, some in the public strongly back the crackdown.

Amin Futouh, a Cairo resident, praised Monday's death sentences. "Those who kill deserve death just as the Quran says," he told AP. "These people have committed murder and they must be killed in return."

But the sweeping verdict also worried even some opponents of the Brotherhood. Beshoy Zakariya, a Christian resident of Cairo, said, "The number (of defendants) is very big, and for sure the verdict is not fair. Some might deserve the verdict and some not."

Human Rights Watch Executive Director for the Middle East Sarah Leah Whitson said the verdicts are the end result of a judicial process that gave defendants no access to their basic rights.

"We are deeply concerned that the dozens of mass trials that are taking place on a daily basis in provinces across Egypt are similarly riddled with due process violations and will also result in outrageous sentences that represent serious miscarriages of justice," she said.