Tunisian police on Saturday arrested political activist Khayam Turki, his lawyer said, noting however that he was not known to be wanted by the authorities.
Turki, 58, had once been considered as a potential candidate to head the government after the resignation of premier Elyes Fakhfakh in 2020, and belongs to the social democratic Ettakatol party.
The lawyer Abdelaziz Essid said Turki had been arrested early morning by police who stormed his house and searched it.
"He was taken to an unknown destination," said Essid, adding Turki had not been "facing any legal proceedings" to justify his arrest. No further details were immediately available.
Ettakatol was allied with the Islamist-inspired Ennahdha party within the government between 2011 and 2014, before the latter became part of the opposition.
Tunisia has seen a spike in the arrest and prosecution of politicians, journalists and others since President Kais Saied seized wide-ranging powers in a dramatic move against parliament in July 2021.
Since then, Saied's opponents have accused him of authoritarianism in the birthplace of the 2011 Arab Spring uprisings.