Thousands of members of the Islamist party Ennahda rallied on Saturday in support of its right to rule and against plans to form a government of technocrats aimed at resolving Tunisia's political crisis.
An estimated 15,000 protesters, many waving party flags and some holding black Salafist banners, thronged Habib Bourguiba Avenue, a Tunis boulevard that was the cradle of the 2011 uprising which ousted president Zine El Abidine Ben Ali.
The demonstration was called to defend the right of Ennahda to continue at the head of the ruling coalition and to oppose Prime Minister Hamadi Jebali's plan to form a government of technocrats.
Jebali, Ennahda's number two, announced his plan in the wake of public outrage over the killing of leftist leader Chokri Belaid that has plunged Tunisia into its worst crisis since the revolution and laid bare divisions within the ruling party.
"God is greatest," and "Supporting Ennahda is a duty," were some of the slogans chanted by the protesters, who also waved banners reading: "For the defence of the Arab-Muslim identity," and "Media of shame and sedition."
The crowd poured scorn on secular opposition leader Beji Caid Essebsi and France, the former colonial power accused of interfering in Tunisian politics, after its interior minister warned last week of "Islamist fascism."
Speaking at the end of Saturday's rally, Ennahda's veteran chief Rached Ghannouchi insisted his party was not ready to relinquish power, underscoring the split amongst its leaders.
"Ennahda... will never give up power, as long as it benefits from the confidence of the people and the legitimacy of the ballot," he told supporters.
The assassination of Belaid, a fierce critic of the ruling Islamists, came after months of failure by the ruling coalition to overhaul the government, and sparked bloody clashes between opposition supporters and police, and attacks on Ennahda offices.
The prime minister has threatened to resign if he fails to secure the support he needs to form his new government.
After meeting the leaders of the main parties on Friday, Jebali said talks on the new administration had been rescheduled for Monday and that a previous Saturday deadline for its formation had been cancelled, with no new date set.
Ennahda was repressed under Ben Ali's regime but emerged as a powerful political force after his overthrow in January 2011, with Ghannouchi returning from 20 years in exile to a hero's welcome.
It won the first post-revolt polls in October 2011, securing the key foreign, interior and justice ministries in the coalition government, and controls the National Constituent Assembly, holding 89 of 271 seats.
But it is divided between moderates, among whom Jebali is the most prominent, and hardliners, represented by Ghannouchi, who are refusing to give up key portfolios, insisting on the party's electoral legitimacy.
The family of Belaid has accused Ennahda of orchestrating his killing, which enflamed simmering tensions between liberals and Islamists in the once proudly secular Muslim nation.
His funeral turned into a massive anti-Islamist protest, thought to be the largest since the revolution.
The murder inquiry has yet to name suspects and the Islamists have strongly denied any involvement.
For some Belaid supporters, the suspicion of blame has fallen on the League for the Protection of the Revolution, a controversial group linked to Ennahda and implicated in attacks on secular opposition groups.
As well as the row over the new government, there is deadlock over the drafting of the constitution, with parliament divided over the nature of Tunisia's future political system.
Tunisia's stability has been further undermined by a spate of attacks blamed on radical Salafists, and by ongoing social unrest, fuelled by the government's failure to improve living conditions