The trial, which began the day before in the capital, prevented nine defendants from appearing in public, on grounds they are too dangerous to be released.
Meanwhile, their lawyers demanded the right of their clients to appear before a judge while numerous demonstrators expressed their rejection of the trial outside the court.
Among the defendants are opposition leaders, diplomats, businessmen, journalists, lawyers and human rights defenders, and several of them have been in prison for more than two years.
There is wide public concern that some of the defendants could face the death penalty if convicted.
Political observers recall that the United Nations recently accused the government of incumbent President Kais Saied of using the judiciary to stifle dissidence, after he dissolved parliament and expanded executive powers in 2021.
During his first term, Saied shook Tunisian political life when he suspended parliament, amended the constitution and ordered the arrest of several of his opponents, including businessmen and executives of his fiercest antagonist, the Islamist-leaning An Nahda party.
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