The main coalition against Tunisian President Kais Saied said Tuesday his administration was using the judiciary to close down opposition to his rule, after several inquiries were opened against its members.
In July last year, Mr. Saied sacked the government, froze parliament and seized far-reaching executive powers, later grabbing control of the judiciary, moves opponents said aimed to install a new dictatorship in the birthplace of the Arab Spring uprisings.
Ahmed Nejib Chebbi, president of the National Salvation Front, said he and three other members had been summoned for investigation after a complaint by another opposition figure from outside the alliance, Abir Moussi.
Ms. Moussi's complaint came after Mr. Chebbi last month accused her of trying to reinstall a dictatorship similar to that of Zine El Abidine Ben Ali who was forced from office in the country's 2011 revolt.
"In just 24 hours, without the complaint even being examined, a decision was already taken to prosecute us," Mr. Chebbi told journalists on Tuesday.
He said the speed of the proceedings showed the complaint was being "instrumentalised" by authorities.
"It's a shoddy piece of judicial theatre and one we won't take part in," he said.
"I won't respond to the summons, and if I'm taken there by force, I will remain silent."
Mr. Chebbi said that any "Tunisian who has an independent opinion or is part of the opposition is a criminal as far as Kais Saied is concerned".
Mr. Chebbi had last month called for Saied to step down, after a December election to a neutered parliament drew turnout of little more than 11 percent.
A lawyer who is defending a group of judges sacked by Kais Saied has also said he is under investigation for allegedly spreading false rumours "in order to undermine public security".
Ayachi Hammami said his summons was based on a controversial decree Mr. Saied issued in September, which provides for prison sentences for anyone spreading "false information or false rumours" in the media or online.
Mr. Hammami said the investigation related to his statements to media late last month that prosecutors asked the top judicial body to strip 13 judges of immunity so they could be tried on terror charges.
In a joint statement on Tuesday, 35 human rights groups voiced their "absolute solidarity" with Mr. Hammami against the "fabricated accusations" he faces.