Tunisia faces a general strike, with tens of thousands expected to take to the streets after the assassination this week of a leftist opposition leader that sparked violent clashes with police.
The General Union of Tunisian Workers called the strike to coincide with the funeral of Chokri Belaid, a lawyer and vocal critic of the ruling Ennahda party who was shot dead outside his home on Wednesday by a lone gunman.
AFP reports the strike call from Tunisia's most powerful trade union comes after the killing triggered demonstrations in both the capital Tunis and the central mining region of Gafsa, amid a deepening political crisis.
Mr Belaid will be buried after weekly prayers in the Muslim country, where a long-established secular tradition has been countered by the rise of one of the region's most powerful Islamist parties.
After an explosion of public outrage over the murder, Prime Minister Hamadi Jebali, who is from the Ennahda party, said in a televised address he would form a new administration of non-political technocrats.
But Ennahda's parliamentary leader Sahbi Atig said later his bloc of MPs had rejected the plans, laying bare deep divisions within the Islamist party and furthering a confused political situation.
"We have rejected this proposal... The head of the government took the decision without consulting the (ruling) coalition or the Ennahda movement," he said.
Any reshuffle would have to be confirmed by the national assembly, reports AFP.
On Thursday police fired tear gas at demonstrators who staged a march despite a huge deployment of security forces in Habib Bourguiba Avenue, the centre of the 2011 uprising that toppled dictator Zine El Abidine Ben Ali and spread to other countries as the Arab Spring uprisings.
Thousands gathered in Habib Bourguiba Avenue in scenes reminiscent of the revolt, on a day when violence in the capital left one policeman dead and protesters torched and ransacked Ennahda offices in a number of towns, including Gafsa.
In Gafsa on Thursday, protesters lobbed petrol bombs at police who responded with volleys of tear gas.
Tunisian lawyers, judges and some teachers had already started a strike on Thursday. Courtrooms stood empty at the main courthouse in Tunis, while hundreds of people gathered outside Mr Belaid's home.
Ennahda has been accused by Belaid's family of being behind the killing -- a charge it vigourously denies.
The Tunisian League for Defence of Human Rights said threats and intimidation were continuing under the Ennahda-dominated government, and called for the protection of political figures.