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

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

Shabeeb said the defense would appeal and the sentences still need the approval of the country’s top religious authority before the executions could take place. It used to be common, under longtime autocrat Hosni Mubarak, who was ousted in 2011, for political prisoners to 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.