Thousands of secular protesters have gathered for a rally in the Tunisian capital in protest against the Islamist-led government in the wake of an opposition politician's assassination.
Police fired tear gas at protesters as opponents and supporters of Tunisia's ruling Ennahda party clashed outside parliament on Sunday, a day after the burial of the second opposition figure slain this year.
Mohamed Brahmi's murder on Thursday outside his home has stoked tensions in the North African nation.
The opposition blames the ruling Ennahda party for the killing and protests have erupted in the capital Tunis as well as other provincial cities.
We will meet this evening to discuss creating a new salvation government and will study the possibility of nominating a new prime minister to replace this failed government.
Opposition figures are calling for the government to resign and the General Union of Tunisian Labour (UGTT) was due to convene Monday "to decide the fate" of the country, its secretary general Sami Tahri said.
Salafists close to the al-Qaeda-linked group Ansar al-Sharia, blamed by the authorities for Brahmi's murder, denied any involvement in an online statement on Sunday.
Brahmi was gunned down in the Ariana suburb of Tunis, his body riddled with 14 bullets, almost six months after the murder of opposition politician Chokri Belaid.
Many Tunisians think the government has not done enough to combat people performing acts of violence in the name of religion.
According to the Reuters news agency, the secular opposition has been considering setting up an alternative "salvation government" to challenge the Islamist-led leadership in the wake of this feeling that the government is not doing enough to protect its citizens.
"We will meet this evening to discuss creating a new salvation government and will study the possibility of nominating a new prime minister to replace this failed government," said Jilani Hammami, a leader of the Salvation Front coalition and Tunisian Workers' Party, on Sunday.
If agreed upon, the move would mark a significant escalation by the country's opposition groups, who say they have no interest in reconciliation with the ruling Islamist Ennahda party.
Tunisians are bracing for what many worry may be one of the most tumultuous and critical periods in their transition to democracy since the toppling of autocratic president Zein El Abidine Ben Ali in 2011, a revolt that inspired uprisings across the Arab world.
The speaker of parliament said on Saturday the government was discussing a new power-sharing deal and urged politicians withdrawing from the transitional Constituent Assembly to reconsider.