MINYA, Egypt (AP) -- After a single session with no defense lawyers present, an Egyptian judge said Tuesday he will issue verdicts next month in a new mass trial of 683 suspected Islamists on charges of murder and attempted murder, a day after he sentenced hundreds to death in a similar trial that raised a storm of international criticism.
The mass trials have raised deep concerns among human rights activists over the lack of due process as Egyptian authorities push swift and heavy prosecutions in their crackdown against Islamists and the Muslim Brotherhood. Some 16,000 have been in arrested in the crackdown since the the military's ouster of President Mohammed Morsi last summer.
Defense lawyers boycotted the trial that began Tuesday in the court in the city of Minya, south of Cairo, to protest the verdicts issued the day before in a separate trial. Despite the lawyer boycott, presiding judge Said Youssef went ahead with the session, hearing testimony, in what the lawyers called a violation of the law.
After the 5-hour hearing, the judge announced that he would issue verdicts in the case at the next session, set for April 28, according to judicial and security officials who attended the sessions and Mohammed Tosson, a defense lawyer who boycotted the session but present in the court building to monitor the results. The officials spoke on condition of anonymity because they were not authorized to discuss the proceedings.
The 683 defendants, all but 68 of whom are being tried in absentia, could also face the death penalty in the case. Among the defendants is the top leader of the Muslim Brotherhood, Mohammed Badie, as well several other senior members of the group. Badie is in custody in Cairo but was not brought to the hearing in Minya for security reasons.
If sentenced to death, Badie would be the most senior figure in the Brotherhood to receive such a sentence since a leading ideologue of the group, Sayed Qutb, was executed in 1966 -- though any verdict against Badie would certainly be appealed.
The previous mass trial that Youssef presided over also held only one session to hear testimony before he held a second session Monday to pronounce the verdicts. Defense lawyers said they were not allowed to present their case during the single session, and they were barred from Monday's hearing, when Youssef pronounced deaths sentenced for 528 of the defendants.
The sentences are subject to appeal and even judicial officials involved in the case said they expect them to be overturned.
But the verdicts stunned Egyptian human rights activists and brought international criticism on Egypt. On Tuesday, the U.N. human rights office called the mass death sentences "unprecedented in recent history" and "a breach of international human rights law."
The U.S. State Department said it "defies logic" that so many defendants could have gotten a fair trial in two sessions. German Foreign Minister Frank-Walter Steinmeier called the verdicts "very alarming" and said "further mass trials must be suspended." The European Union's foreign policy chief, Catherine Ashton, called on Egyptian officials to ensure "defendants' rights to a fair and timely trial."
Sixteen Egyptian rights groups said they were "extremely concerned" about the court verdict, saying they constitute "a dangerous, unprecedented shift in the Egyptian judiciary's treatment of such cases and represent a grave violation of both the right to a fair trial and the right to life."
The Justice Ministry on Tuesday issued a statement in reaction to the criticism, underlining that the defendants have a right to appeal the verdicts to the Court of Cassation, which can order a retrial. If the retrial reaches a similar verdict, the defendants can appeal to the higher court again, it said.
The two trials in Minya are connected to a wave of rioting and mob attacks on police stations by Morsi supporters in August, sparked when security forces stormed two pro-Morsi protest camps in Cairo, killing more than 600 people.
In the latest trial, the defendants are charged with murder over the death of two policemen in an attack on a police station in the town of el-Adawa. They are also charged with attempted murder of five people -- including a Christian resident -- as well as with membership in a terrorist group and with aiding, financing and providing weapons to carry out a terrorist attack.
The government has branded the Brotherhood a terrorist group, a claim it denies.
As a show of protest over the verdicts in the first trial, defense lawyers boycotted Tuesday's tribunal.