An Egyptian court in the southern city of Minya sentenced 683 people to death Monday in the most recent of a series of mass trials that have alarmed the international community.

The ruling came one month after 529 people were sentenced to death in a similar mass trial in the same courtroom, and it coincided with a visit to Washington by Egypt’s foreign minister in an effort to smooth relations between the United States and one of its most significant allies in the Middle East.

The Obama administration quickly condemned the ruling, saying that it defied “even the most basic standards of international justice.”

“Egyptian leaders must take a stand against this illogical action and dangerous precedent, recognizing that the repression of peaceful dissent will fuel the instability and radicalization that Egypt says it wishes to prevent,” White House press secretary Jay Carney said in a statement.

Those sentenced to death were all alleged supporters of the ousted Islamist president Mohamed Morsi, who was toppled last summer in a military coup. They included Mohammed Badie, the “supreme guide” of Morsi’s Muslim Brotherhood, which captured the lion’s share in Egypt’s first democratic elections, held in 2012.

All but 37 of the previous death sentences have been commuted to life imprisonment, under a review by Egypt’s highest religious authority, it was announced Monday.

The most serious charge in Monday’s case was the killing of a single police officer during clashes between security forces and Morsi’s supporters across the nation last summer. The clashes broke out after Egyptian security forces launched deadly raids on pro-Morsi protest camps in the capital.

The defendants were barred from attending their own trial, which lasted only a few minutes, defense attorneys said. It was unclear what evidence the court had used to convict the men, who were described by families and defense attorneys as ordinary townspeople.

Defense attorneys said they would appeal the verdict. But anger was palpable in Minya and the nearby village of Al-Edwa, home to nearly all of the 683.

“It’s all going to hell — the judiciary and everything else,” said Mohamed Saber, who sells juice and cigarettes from a roadside stand near the courthouse in Minya, where police and soldiers stood guard Monday. “How can you sentence so many people for just one crime?”

Egypt’s new military-backed government has increasingly cracked down on voices of dissent in the months since the coup, jailing tens of thousands of Islamist members of the now-banned Muslim Brotherhood as well as liberal democracy activists, journalists and university students.

Also on Monday, an Egyptian court banned the April 6 Youth Movement, one of the foremost pro-democracy activist groups that rallied Egyptians to take to the streets in 2011 against longtime autocrat Hosni Mubarak.

In Washington, Egypt’s foreign minister, Nabil Fahmy, avoided responding substantively to questions about the death sentences and argued that all Egyptian institutions, including the judiciary, are evolving.

“The whole society is going through a transformation,” he said.

He asked attendees at an event at the Center for Strategic and International Studies not to “jump to conclusions” about how court cases were being handled.

While Fahmy said the government was striving to build a more “inclusive” nation, he defended the crackdown on the Muslim Brotherhood, comparing it to steps the United States took in the aftermath of the Sept. 11, 2001, attacks.

“When you face terrorism and exceptional circumstances, you respond,” he said.

Of the 683 men sentenced on Monday, only 70 are in custody, said Khaled Koumi, a defense attorney in the case. None of the men were allowed to appear in court for their trial, which involved only two short hearings, Koumi said.

“All we can do now is appeal,” he said, calling the verdict a “sham.”

Ahmed Shabeeb, a lawyer from the village of Matay, described the arrests and prosecution as arbitrary from the start.

“Anybody who had any dealings with the Brotherhood was taken in,” said Shabeeb, who represents 30 of his fellow villagers who were sentenced to death last month. “If you greeted a Brotherhood member 10 years ago, you were arrested.”

His clients, ranging in age from 17 to 60, are “doctors, businessmen and manual laborers,” among others, he said. One of his clients “wasn’t even in the country” when the events in question occurred, he said.

Among those sentenced was Haggag Saber, a 35-year-old stationery shop owner who was taking his mother to have an operation in Cairo on Monday when he heard the news. “We were shocked,” he said.

Last week, the Obama administration said it would deliver 10 Apache helicopters to Egypt, marking a partial resumption of Washington’s annual $1.3 billion in military aid, which was suspended after last summer’s coup.

Lara El Gibaly in Minya and Ernesto Londoño in Washington contributed to this report.