The head of a leading rights group went on trial in Belarus on Wednesday on charges of tax evasion in a case that has stoked international outrage against the regime of President Alexander Lukashenko. Ales Beliatsky, head of Vyasna (Spring), was detained on August 4 after authorities received information from Lithuania and Poland about bank accounts he held in their countries to support his work at home. Rights activists say the trial is part of an unprecedented crackdown Lukashenko unleashed against the opposition following his controversial re-election last December. Dressed in a red shirt and looking pale and haggard with his grey hair closely cropped, Beliatsky appeared in court placed inside an iron cage and said he was being punished for his beliefs. \"I am convinced that I am being persecuted for my political views, for human rights activities, and for my criticism of the current authorities,\" he said. Prosecutor Valery Saikovsky said the rights activist had 550,000 euros in his accounts in Lithuania and Poland but did not declare those funds. \"Being a Belarussian tax resident and knowing about the duty to file tax returns, he avoided paying a large amount of taxes,\" Saikovsky said, accusing him of evading a debt of around 21,000 euros ($30,000) in taxes. Beliatsky denies any wrongdoing, saying he could not understand what amount should be considered his income. He confirmed that several foreign rights organisations as well as the Dutch foreign ministry had sent money to his foreign accounts to support his rights activities. Vyasna lost its official registration after repeated run-ins with the Belarus authorities in 2003 and was forced to keep its offices and finances in European capitals. His colleagues said they were bracing for the worst. \"We are expecting the harshest verdict possible,\" Vyasna deputy chairman Valentin Stephanovich told reporters. The courtroom was bursting at the seams, with former political prisoners, rights activists and diplomats from Britain, Germany, Lithuania and the United States attending the hearing. If convicted, Beliatsky faces up to seven years in prison. Lithuania and Poland have said they regretted providing the data to the authoritarian regime of Lukashenko, who has stayed in power in the ex-Soviet state for the past 17 years. The Lithuanian justice ministry said the information it had provided to Belarus could not be used as evidence in the trial. \"Several months ago we officially informed Belarus authorities that we had recalled the information provided by the Lithuanian justice ministry in line with the legal assistance treaty and that it cannot be used as legal evidence in court,\" Justice Minister Remigijus Simasius said in a statement. \"Legal assistance provisions and the system of international cooperation is intended to track down terrorists and criminals, to ensure safety and cannot be used to serve political interests,\" the statement said. Human Rights Watch this week called on Lukashenko to immediately release the activist. \"Human rights defenders like Beliatsky are being forced into a legal grey area that the government exploits to punish them,\" said Hugh Williamson, Europe and Central Asia director at the activist group. \"In reality, what happened to Ales Beliatsky is pure entrapment.\"