“The people have come to bring down the government,” the protesters chanted as they brandished pictures of some of the dozens of people killed by security forces during the uprising against president Zine El Abidine Ben Ali.
They broke through security cordons to reach the doors of the building in central Tunis, but the rally remained mostly peaceful and security was low. A police source estimated the number of protesters at around 3,000.
The new transitional government, put in place after Ben Ali resigned and fled to Saudi Arabia on January 14, has unveiled unprecedented freedoms, but it still includes Ghannouchi and other old-regime figures.
“We have come to bring down the rest of the dictatorship,” said Mohammed Layani, an elderly man draped in a Tunisian flag, who arrived with hundreds of others from the region in central Tunisia where the uprising began.
Samit, a young man from the city of Kairouan, said: “We are outcasts in our own country. All the wealth goes to the coast. But our main demand is freedom before bread. We want this fascist and corrupt regime to fall.”
On a sign reading “Prime Minister’s Office,” a protester had scrawled: “Ministry of the People”. A placard held up during the rally read: “They stole our money, they won’t steal our revolution.”
The protest was supported by the General Union of Tunisian Workers, best known under its French acronym UGTT, which played a key role in anti-Ben Ali protests and has refused to recognise the fledgling government.
The state news agency TAP, meanwhile, said security forces had detained two more figures linked to the old regime — Senate chief Abdallah Kallal and Ben Ali adviser Abdel Aziz Ben Dhia.
The authorities say they have arrested 33 members of Ben Ali’s family.
Public assemblies of more than three people are officially banned under a state of emergency that remains in place, along with a night-time curfew.
Schools and universities are to reopen this week.