Tunisia's political crisis is deepening after the assassination of a leading opposition leader earlier this week.The killing of anti-Islamist politician Chokri Belaid sparked violent protests. The prime minister then announced plans for a new, technocratic government.
But the ruling Islamist party Ennahda rejected the move, saying Hamadi Jebali "did not ask the opinion of his party".
Meanwhile, police have fired tear gas to disperse protesters in Tunis and in the central town of Gafsa.
The Gafsa demonstrators, who were observing a symbolic funeral for Chokri Belaid, rallied outside the governor's office, throwing stones and petrol bombs at the police.
As riot police fired tear gas towards angry youths on Bourguiba Avenue, the scene was disturbingly reminiscent of what happened on this very avenue two years ago. Even the chanting was the same: "We want the downfall of the regime."
Earlier, four opposition groups - including Mr Belaid's Popular Front - announced that they were pulling out of the country's national constituent assembly in protest.
The country's largest trade union, the General Union of Tunisian Workers, called a general strike for Friday.
Reacting to the escalating crisis, France said it would close its schools in the capital Tunis on Friday and Saturday.
Mr Belaid's killing has brought to a new pitch a long-simmering political crisis in Tunisia, with secularists and liberals accusing the Islamists of amassing too much power, the BBC's Sebastian Usher says.
Ennahda denies opposition claims that it was behind the assassination in Tunis.
Credit first two photos Amine Boufaied, third one Kais Zriba/Nawaat