An Egyptian court has sentenced 529 people to death in the largest capital punishment case on record in Egypt, judicial authorities said Monday.

The alleged supporters of ousted Islamist president Mohamed Morsi were convicted on charges of killing a single police officer, the attempted murder of two other officers, and attacking a police station in the Nile Valley city of Minya in August. Sixteen people were acquitted.

The mass sentencing underscored the severity of an ongoing campaign by Egypt’s military-backed leaders to silence opposition, eight months after a military coup ousted Morsi, the country’s first democratically elected leader.

It was unclear what evidence prosecutors presented to support Monday’s ruling, which came after only two court sessions. A defense attorney in the case said that the defense was never given access to the evidence and that none of the defendants — or their attorneys — were allowed in court for the verdict.

When defense attorneys objected to court procedures during the first hearing Saturday, security personnel threatened members of the defense team to silence them, said one of the lawyers, Ahmed Shabeeb.

“This whole process is a sham,” he said.

Shabeeb said that the defense would appeal and that the sentences still need the approval of the country’s top religious authority before the executions could take place.

Under longtime autocrat Hosni Mubarak, who was ousted in 2011, political prisoners could spend years on death row before sometimes being acquitted.

But rights groups said the mass sentencing set a fearsome precedent. “This has never happened in the history of the Egyptian judiciary, or the history of any judiciary, as far as I know,” said Mohamed Zera, a lawyer with the Cairo-based Human Rights Center for the Assistance of Prisoners.

The closest comparison, he said, was the execution of 106 people after convictions in military courts at “the peak” of Mubarak’s effort to quell an Islamist insurgency in the 1990s. “Today we’re talking about one verdict in one case,” he said, “and it’s more than the number sentenced over the course of an entire decade.”

The United States was “deeply concerned, and I would say actually pretty shocked,” about the mass death sentences, said Marie Harf, a State Department spokeswoman. “It defies logic” and “certainly does not seem possible that a fair review of evidence and testimony, consistent with international standards,” could have been conducted over a two-day period, she said.

Harf said that the United States was raising its concerns with the Egyptian government but that “it’s an important relationship [that we] don’t want to completely cut off.”

Egypt’s security forces have jailed more than 16,000 people since the coup in July, in the largest state-sponsored crackdown in nearly two decades, the Associated Press reported this month.

Over the past five months, the crackdown has widened well beyond the scope of Morsi’s Islamist allies, snagging the country’s most prominent liberal activists, well-known journalists and scores of university students.

Deadly clashes erupt frequently between police and anti-

government demonstrators, particularly around university campuses.

In November, the state banned protests held without government approval, giving security forces and prosecutors broad authorization to go after all traces of political opposition.

In December, the state declared Morsi’s Muslim Brotherhood — long the most organized political group in the country — a terrorist organization.

Many of those detained have appeared before courts in hasty sessions that lack transparency and evidence, rights groups and defense lawyers say. Other defendants, including several former members of the Morsi administration, have languished in maximum-security prisons for nearly eight months without trial, lawyers and relatives say.

Very few police officers have faced similar treatment, despite reports of widespread human rights abuses on the streets and in detention centers. This month a police captain was sentenced to 10 years in prison for the gassing deaths in August of 37 prisoners in a stationary transport van, the Guardian newspaper reported. The victims, not all of them Islamists, had been rounded up in the vicinity of pro-Morsi demonstrations.

Monday’s convictions also related to the wave of violence and protests that rippled across the country last August, after Egyptian security forces raided pro-Morsi protest camps in Cairo, killing more than a thousand of the ousted president’s supporters.

The backlash touched off clashes between police and other Islamist protesters nationwide and saw dozens of police stations, military installations and churches attacked.

Also Monday, three journalists — including an Australian and a Canadian — from the Al Jazeera English satellite TV network, along with a handful of co-defendants, appeared in court for their third hearing on terrorism charges. The news network and the journalists’ attorneys have said that the charges are political and that the men were arrested for doing their jobs.

They have been imprisoned since December. In the previous hearing this month, prosecutors presented their evidence in the case, consisting of computers, hard drives, cameras and other equipment typical of a newsroom.

Karen DeYoung in Washington contributed to this report.