A wave of raids and arrests has targeted opposition figures and government critics recently.
A Tunisian “anti-terrorism” investigative judge has imprisoned two prominent politicians and a high-profile businessman, their defence team has said.
Lawyers for Abdelhamid Jlassi and Khayam al-Turki, both critics of President Kais Saied, and businessman Kamel Ltaif said the judge made the decision on Saturday.
They added that the defence team for the three said it had boycotted a plea hearing because the conditions for a fair trial had not been met.
All three were arrested amid a security crackdown that has seen a series of raids and arrests of opposition politicians, activists, protest organisers, a media figure, judges and an influential business leader.
The 12 people arrested as of Saturday include Chaima Aissa and Jaouhar Ben Mbarek, leaders of the National Salvation Front opposition coalition, as well as Issam Chebbi, the head of the opposition Jomhouri (Republican) Party.
All those arrested were connected to criticism of Saied or efforts to mobilise protests against the president, who in 2021 shut down parliament, dismissed the government and moved to rule by decree before rewriting the constitution.
Last week, Rached Ghannouchi, the head of the opposition Ennahdha party and speaker of an elected parliament that Saied formally dissolved last year, was also summoned for questioning.
Opponents have called the consolidation of power a coup that pulled apart the democracy built after a 2011 revolution that made the country the birthplace of the Arab Spring.
Saied has denied a coup, saying his moves were legal and necessary to save Tunisia from chaos.
His government has not commented on the timing of the arrests, but he has called his critics traitors and criminals and has said some of those arrested were behind food shortages that economists have blamed on weak state finances.
Earlier this month, he said those arrested had committed “conspiracy against internal and external state security”, without specifically naming any of the individuals.
On Friday, Human Rights Watch said the government was pursuing the crackdown “with utter abandon”.
The group noted that many had been charged under terrorism laws that allow detention without charges for up to 15 days and ban access to a lawyer for 48 hours.
“The message in these arrests is that if you dare to speak out, the president can have you arrested and publicly denounce you while his henchmen try to build up a file against you based on remarks you made or who you met,” Salsabil Chellali, the Tunisia director for the rights group, said in a statement.
Former colonial power France, meanwhile, expressed “concern at the recent wave of arrests in Tunisia and calls on the Tunisian authorities to ensure respect for individual freedoms and public freedoms, in particular, freedom of expression”.
For its part, the National Salvation Front on Friday promised to continue efforts to unite opposition groups against Saied.