Move comes a day after party leader Ghannouchi was arrested in an ongoing crackdown on Tunisia’s opposition.
Ahmed Gaaloul, an adviser for Ghannouchi, told Al Jazeera that police were conducting a search of the building on Tuesday, and that it would be closed for a minimum of three days.
“A police unit showed up at the party’s main headquarters (in Tunis) and ordered everyone there to leave before closing it,” Riadh Chaibi, a senior party official, told AFP.
“The police also closed the other offices of the party elsewhere in the country and prohibited any meeting in these premises,” Chaibi added.
Ghannouchi, Ennahdha’s longtime leader, was arrested at his home in the capital, Tunis, late on Monday, the latest in a string of opposition figures held.
Ennahdha, a self-styled “Muslim Democrat” party, was the largest in Tunisia’s parliament before President Kais Saied dissolved the chamber in July 2021.
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 claims those detained were “terrorists” involved in a “conspiracy against state security”.
Ennahdha vice-president Mondher Lounissi told a news conference late on 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 he warned that Tunisia faced a civil war if any of the country’s political forces – including political Islamists and leftists – were excluded.
A source at the interior ministry quoted by Tunisian media confirmed that Ghannouchi’s arrest was linked to these statements.
‘New phase in crisis’
Ghannouchi was the speaker of Tunisia’s parliament before Saied dissolved it and went on to seize wide-reaching powers through a series of moves opponents have dubbed a “coup”.
Opponents of Saied accuse him of reinstating autocratic rule in Tunisia, which was the only democracy to emerge from the Arab Spring uprisings in the Middle East region more than a decade ago.
After his dramatic power grab, he has ruled by decree, and last year rammed through a constitution that gave his office unlimited powers and neutered parliament.
Human rights groups have criticised the arrests, which targeted leading figures of the National Salvation Front (NSF), the main opposition coalition, which includes Ennahdha.
“The arrest of the leader of the most important political party in the country, and who has always shown his commitment to peaceful political action, marks a new phase in the crisis,” NSF head Ahmed Nejib Chebbi said late on Monday.
“This is blind revenge against opponents,” he added.
Ghannouchi appeared in court at the end of February on terror-related charges after being accused of calling police officers “tyrants”.
Ghannouchi was exiled for more than two decades under late dictator Zine El Abidine Ben Ali but returned following the country’s 2011 uprising to become a dominant figure in Tunisian politics.