Media playback is unsupported on your device Media caption The conduct of the trial has been described as "unprecedented", the BBC's Orla Guerin reports 
 
 The UN human rights commissioner has condemned an Egyptian court's decision to sentence to death 528 supporters of ousted President Mohammed Morsi. 
 
 A spokesman for Navi Pillay said the "cursory mass trial" was "rife with procedural irregularities" and breached international human rights law. 
 
 The defendants were found guilty on Monday of charges relating to an attack on a police station in Minya in August. 
 
 Another 683 Morsi supporters went on trial at the same court on Tuesday. 
 
 They include the Muslim Brotherhood's general guide, Mohammed Badie, and the chairman of its Freedom and Justice Party (FJP), Saad al-Katatni. 
 
 Later, security forces clashed with hundreds of Minya University students protesting against the trials. 
 
 Tear gas was fired at the students after they blocked a main road, threw stones and set an armoured police vehicle on fire. 
 
 'Unprecedented' 
 
 There has been widespread condemnation of Monday's decision by the Minya Criminal Court to sentence 528 people to death for their alleged participation in an attack on a police station in the central city in mid-August, in which a police officer was killed. 
 
 The incident took place in the immediate aftermath of an operation by security forces to break up two sit-ins in the capital Cairo that left almost 1,000 people dead. The sit-ins were set up by supporters of Mr Morsi's after he was overthrown by the military the previous month. 
 
 The trial, at which more than three-quarters of the defendants were not present, is reported to have lasted less than an hour on Saturday. 
 
 The prosecution did not put forward evidence implicating any individual defendant, even though it had compiled significant evidence, and the court prevented defence lawyers from presenting their case or calling witnesses, according to Human Right Watch. 
 
 A second session was held on Monday solely to announce the verdict. 
 
 Media playback is unsupported on your device Media caption The 528 Morsi supporters sentenced to death on Monday were convicted of murder and damaging property, as Orla Guerin reports 
 
 On Tuesday, a spokesman for the UN High Commissioner for Human Rights, Rupert Colville, told a news conference in Geneva: "The astounding number of people sentenced to death in this case is unprecedented in recent history." 
 
 "The mass imposition of the death penalty after a trial that was rife with procedural irregularities is in breach of international human rights law." 
 
 Sixteen Egyptian rights groups voiced concern, saying the trial constituted a "dangerous, unprecedented shift in the Egyptian's judiciary's treatment of such cases" and represented "a grave violation of both the right to a fair trial and the right to life". 
 
 But Egypt's interim government defended the court, insisting that the sentences had been handed down only "after careful study". 
 
 The state-run al-Ahram newspaper said the court would issue its final verdict on 28 April after Egypt's grand mufti, who under the law must ratify each death sentence before it can be carried out, had passed judgement. 
 
 The defendants may then appeal. Legal experts said a higher court would most probably order a retrial or reduce their sentences. 
 
 Boycott 
 
 Mr Colville also expressed concern about the 683 people who went on trial at the Minya Criminal Court on Tuesday on similar charges relating to an attack on another police station in which no-one died. 
 
 The BBC's Orla Guerin, who is outside the courthouse, says that after an opening session lasting just a few hours the case was adjourned until 28 April, when the judge, Said Youssef, said a verdict would be given. 
 
 Media playback is unsupported on your device Media caption Head of Appeals Court Ahmed Midhat El-Maraghy: "The court has the ultimate say in assessing the punishment and no one can interfere with that" 
 
 Critics will ask how the fate of so many people could be decided after the briefest of trials, our correspondent says. And, she adds, there were two key elements missing - most of the defendants and any of their lawyers. 
 
 Only 62 defendants reportedly appeared in court, with officials saying Mr Badie and Mr Katatni could not attend for security reasons, while the defence team staged a boycott in protest at the preceding trial. 
 
 "As lawyers, we haven't seen anything like what happened here yesterday in our entire professional lives and we will not see anything like it until our deaths," Khaled Fouda of the Minya lawyers' syndicate said. 
 
 Despite the boycott, the judge heard testimony from witnesses and questioning several of the defendants before adjourning the case. 
 
 The wife of one of the accused in Tuesday's case told the BBC she feared the verdict had been decided in advance. She said her husband was an innocent man who had been arrested while picking up their daughter from hospital. 
 
 The 1,200 defendants in the two cases in Minya are among more than 16,000 Egyptians arrested over the past eight months, according to figures recently provided by senior interior ministry officials. They include about 3,000 top or mid-level Brotherhood members. ||||| After a single session with no defence 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. About 16,000 have been in arrested in the crackdown since the the military’s ouster of President Mohammed Morsi last summer. 
 
 Defence 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 five-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 defence 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. Defence 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 United Nations 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, defence lawyers boycotted Tuesday’s tribunal. 
 
 “As lawyers, we haven’t seen anything like what happened here yesterday in our entire professional lives and we will not see anything like it until our deaths,” Khaled Fouda, of the Minya lawyers’ syndicate, told a press conference announcing the boycott. 
 
 One of the boycotting defence lawyers, Yasser Zidan, said the judge violated the law by not postponing Tuesday’s session until new lawyers could be appointed for the defendants. “This is just another disaster,” Zidan said. “This judge smashed the rock of justice with his own hands. He is inventing a new law.” 
 
 According to the judicial and security officials, the judge questioned nearly 20 witnesses, including policemen and civilians who saw the police station attack. A collection of 70 video clips and 200 photos from the attack were also submitted into evidence. 
 
 A few kilometres away from the court, clashes erupted between security forces firing tear gas and rubber bullets and Islamist students at Minya University who chanted slogans against the verdicts and the military. 
 
 Roads around the Minya court building were blocked by cement blocks and metal barricades, manned by security forces and masked special forces. Armored vehicles patrolled the streets and shops in the vicinity of the court were shut down. 
 
 Security forces kept small groups of protesters, including relatives of the defendants, and traffic away from the area. 
 
 In a nearby coffee shop, relatives of the defendants sat to sip tea and have breakfast. One of them, 45-year-old al-Hawari, a farmer who spoke on condition he be identified only by his first name for fear of police harassment, said his cousins and neighbours are among the defendants. He insisted they were not involved in killings or violence. 
 
 “These are all fabrications. Where is the evidence?” said al-Hawari, dressed in traditional robes. Still, he acknowledged that on the day of the mob attack in the el-Adwa police station, many people were involved in fighting, shooting and rioting near the police station to take revenge from “injustice inflicted by the police officers.” 
 
 “We already know the verdict. God be with us,” he said with a sigh. 
 
 Maggie Michael reported from Cairo.
– A day after sentencing 529 people to death, Egypt launched another mass trial today, this time accusing 683 Muslim Brotherhood members—including the Brotherhood's top spiritual leader, Mohammed Badie—of crimes including murder and inciting violence in connection with a riot at a police station in Minya. Only 68 defendants were actually in court, the AP reports. Most of the rest are being tried in absentia, though some jailed Brotherhood honchos, including Badie, were kept out of court for security reasons. Also absent: Many defense lawyers, who are boycotting the trial in protest of yesterday's sentencing; the judge who handed out those death sentences is presiding today. By law the lawyers' absence should have halted the trial, but the judge forged ahead. "This judge smashed the rock of justice with his own hands," one said. "He is inventing new law." The 683 are accused of killing two policemen, though according to the BBC no one was actually reported killed in the Minya attack—which followed police raids that killed almost 1,000 protesters in Cairo.