Tunisian authorities shuttered the headquarters of the opposition Ennahdha party on Tuesday, a day after arresting its leader Rached Ghannouchi, a senior party official said.

"A police unit showed up at the party's main headquarters (in Tunis) and ordered everyone there to leave before closing it," Riadh Chaibi said.

"The police also closed the other offices of the party elsewhere in the country and prohibited any meeting in these premises," he told AFP.

The move came after Ennahdha's veteran leader Ghannouchi was arrested at his home in the capital Tunis, the latest in a string of opposition figures held.

Ennahdha was the largest party in Tunisia's parliament before President Kais Saied dissolved the chamber in July 2021.

The party's vice-president, Mondher Lounissi, told a news conference late Monday that Ghannouchi had been taken to a police barracks for questioning and that his lawyers had not been allowed to attend.

His arrest came after media reports in which he allegedly said Tunisia would be threatened with "civil war" if political Islam, from which his party originated, were eradicated there.

A source at the Interior Ministry quoted by Tunisian media confirmed that Ghannouchi's arrest was linked to these statements.

Since early February, authorities in the North African country have arrested more than 20 political opponents and personalities.

They have included politicians, former ministers, businessmen, trade unionists and the owner of Tunisia's most popular radio station, Mosaique FM.

Saied, 65, claims those detained were "terrorists" involved in a "conspiracy against state security."