A Russian court has ordered that the latest trial of Alexei Navalny be held behind closed doors, as the Kremlin critic faces extremism charges that could mean his prison time is extended for decades. Navalny is being tried at the maximum-security prison where he is jailed: IK-6 penal colony, about 150 miles (250km) east of Moscow. “The court has decided to make the Navalny trial closed,” said a Moscow city court spokesperson, Vadim Pozhelayev, several hours after proceedings began. He called for the press to leave the building. “Shameless – no conscience or honour,” Navalny’s father, Anatoly, said of the court’s decision as he was told to leave. Navalny, 47, once mobilised massive anti-Kremlin protests but is now serving a nine-year prison sentence on embezzlement charges that his supporters see as punishment for his political work. He was arrested in 2021 on his arrival in Moscow from Germany, where he had been recovering from a poisoning attack that he blamed on the Kremlin. Navalny, who has complained of health problems since being jailed and has experienced significant weight loss, could have 30 years tacked on to his jail term. He said prosecutors had provided him with 3,828 pages describing all the crimes he is alleged to have committed while in prison. Navalny said: “Although it’s clear from the size of the tomes that I am a sophisticated and persistent criminal, it’s impossible to find out what exactly I am accused of.” He has been charged with financing extremist activity, publicly inciting extremist activities and “rehabilitating the Nazi ideology”, among other offences. Navanlny has denounced Vladimir Putin’s war in Ukraine, describing it as a tragedy and saying Moscow’s defeat is inevitable. On Monday, his team announced the launch of a campaign to deter Russians from supporting the conflict. In a post online, Navalny’s team said it was planning a “long, stubborn and exhaustive but fundamentally important campaign where we will turn people against the war. Against the dead end that Putin crazily and dumbly put us in on February 24, 2022. It said it planned to fundamentally change Russian public opinion within months. Russia has introduced strict laws banning criticism of its army’s actions in Ukraine. Organisations and lawyers that have campaigned for Russians critical of the offensive have faced increasing pressure. On Monday, Russian state media reported that Agora, a leading human rights group that provides legal help in political cases, had been labelled as “undesirable”. While Navalny has been the target of several legal cases, this is the first formally political case against him, his team said. “He is being tried for his political work,” Navalny spokesperson Kira Yarmysh told AFP before the trial. In April, Navalny said he had been told he would be judged by a military tribunal over “terrorism” charges. He could face life in prison, he said. Navalny’s team say he has been harassed in prison, where he was kept in a “punishment cell” for perceived transgressions. The opposition leader – a lawyer by training – has taken prison officials to court to retain access to what he sees as basic prisoner rights. Navalny built a huge social media following by producing videos providing evidence of systemic corruption among Russian elites. He still communicates on social media through his team. Navalny had set up a network of campaign offices across the country and aimed to run for president in 2018, but election authorities did not allow him to challenge Putin. His offices were designated “extremist” organisations in 2021. In mid-June, a Russian court sentenced Liliya Chanysheva, the head of Navalny’s headquarters in the central city of Ufa, to seven and a half years in prison.