Tunisian police on Thursday detained Ezzedine Hazgui, a fierce critic of President Kais Saied and the father of another prominent dissident, Jawher Ben Mbarek, Hazgui's daughter said.
Police detained Hazgui at his home and took his phone, his daughter Dahlia Ben Mbarek, a lawyer, said by phone.
The arrest comes amid a crackdown on dissent this month that has targeted prominent critics of Saied including opposition politicians, activists, protest organisers and media figures as well as an influential business leader and two judges.
Police on Wednesday surrounded the home of Hazgui's son Jawher Ben Mbarek, but he was not there and has not been detained, according to his sister.
The United States has voiced deep concern at the arrests and rights groups have urged Saied to reverse course.
The president shut down parliament and seized most powers in 2021, moving to rule by decree and writing a new constitution that he passed through a referendum with a low turnout last year.
His critics, including most of the major political parties that were in the parliament he dissolved, accuse him of a coup that has unpicked the democracy created after Tunisia's 2011 revolution that triggered the Arab spring.
Saied says his actions were legal and necessary to save Tunisia from chaos, and has accused his opponents of being traitors and criminals.
(Writing by Angus McDowall; Editing by Raissa Kasolowsky)