(Updates funeral, adds Tunis Air suspends flights, French warning)
* Mourners chant anti-Islamist slogans
* General strike held in protest at lawyer's murder
* Prime minister's plan for caretaker government fails
* Tunis Air suspends flights due to strike
By Tarek Amara and Alistair Lyon
TUNIS, Feb 8 (Reuters) - Tens of thousands of mourners chanted anti-Islamist slogans on Friday at the Tunis funeral of secular opposition leader Chokri Belaid, whose assassination has plunged Tunisia deeper into political crisis.
Crowds surged around an open army truck carrying Belaid's coffin, draped in a red and white Tunisian flag, from a cultural centre in the slain leader's home district of Jebel al-Jaloud. Demonstrators with flags and banners packed surrounding streets.
"Belaid, rest in peace, we will continue the struggle," they chanted, holding portraits of Belaid, who was shot dead outside his home on Wednesday by a gunman who escaped on the back of a motorcycle.
Some shouted slogans against Rachid Ghannouchi, leader of the ruling Islamist Ennahda party. "Ghannouchi, assassin, criminal," they chanted. "Tunisia is free, terrorism out."
Tunisia, cradle of the Arab uprisings, is riven by tensions between dominant Islamists and their secular opponents, and by frustration at the lack of social and economic progress since President Zine al-Abidine Ben Ali was ousted in January 2011.
In Sidi Bouzid, the southern town where the revolt began, about 10,000 protesters gathered to mourn Belaid and shout slogans against Ennahda and the government, witnesses said.
Hundreds of riot police deployed in Habib Bourguiba Avenue, a flashpoint for protests in the Tunisian capital. Banks, factories and some shops were closed in response to a strike called by unions in protest at Belaid's killing, but buses were running normally.
Tunis Air suspended all its flights because of the strikes, a spokesman for the national airline said, adding that flights operated by other airlines were not affected.
However, airport sources in Cairo said Egypt's national airline EgyptAir had cancelled two flights to Tunisia after staff at Tunis airport joined the general strike.
After Belaid's assassination, Prime Minister Hamdi Jebali, an Islamist, said he would dissolve the government and form a non-partisan cabinet of technocrats to rule until elections could be held.
But his own Ennahda party and its secular coalition partners complained they had not been consulted, casting doubt over the status of the government and compounding political uncertainty.
No one has claimed responsibility for the killing of Belaid, a lawyer and secular opposition figure.
ENNAHDA OFFICES TARGETED
His family have blamed Ennahda but the party has denied any hand in the shooting. Crowds have attacked several Ennahda party offices in Tunis and other cities in the past two days.
While Belaid had only a modest political following, his criticism of Ennahda policies spoke for many Tunisians who fear religious radicals are bent on snuffing out freedoms won in the first of the revolts that rippled through the Arab world.
"Criminals assassinated Chokri, but will not assassinate his struggle," his widow Besma Khlifi said on Thursday. "My sadness ended when I saw thousands flocking to the streets ... At that moment I knew that the country is fine and men and women in my country are defending democracy, freedom and life."
All three ruling parties and sections of the opposition rebuffed Jebali's plan to create a small, technocrat government to take over day-to-day matters until elections could be held, demanding they be consulted before any such move.
"In the likely event that there is no agreement, civil unrest will increase, reaching a level that cannot be contained by the police," said Firas Abi Ali of the London-based Exclusive Analysis think-tank.
"If unrest continued for more than two weeks, the army would probably reluctantly step in and back a technocrat government, as well as fresh elections for a new Constituent Assembly."
The economic effect of political uncertainty and street unrest could be serious in a country which has yet to draft a new constitution and which relies heavily on the tourist trade.
Mohamed Ali Toumi, president of the Tunisian Federation of Travel Agencies, described the week's events as a catastrophe that would have a negative impact on tourism, but he told the national news agency TAP no cancellations had been reported yet.
France, which had already announced the closure of its schools in Tunis on Friday and Saturday, urged its nationals to stay clear of potential flashpoints in the capital.
"Unless unavoidable, it is best to stay away from the city centre today, and steer clear of demonstrations and major road crossings or sensitive buildings," said Helene Conway-Mouret, minister in charge of French people living abroad.
The Austrian foreign ministry issued a similar warning.
The cost of insuring Tunisian government bonds against default rose to its highest level in more than four years on Thursday and ratings agency Fitch said it could further downgrade Tunisia if political instability continues or worsens. (Additional reporting by Alexander Dziadosz in Cairo, Brian Love in Paris and Michael Shields in Vienna; Editing by Andrew Heavens)