Tunisian police have arrested Chaima Issa, a prominent opponent to President Kais Saied and a senior official in the National Salvation Front.
Earlier, Issam Chebbi, leader of the Republican Party and another fierce critic of the president was also arrested.
Lawyers acting for the detained head of a private Tunisian radio station say he is facing politically motivated money laundering charges.
Noureddine Boutar - arrested earlier this month - is head of the popular Mosaique FM.
The station has long been critical of Mr Saied.