Tens of thousands have taken to the streets for the funeral of the assassinated opposition leader Chokri Belaid, amid fears of escalating violence in the country.
Protesters surrounded an army truck carrying Mr Belaid's coffin, draped in a red and white Tunisian flag, to the cemetery in the capital Tunis as a helicopter circled overhead.
Police fired tear gas and there were minor clashes as groups of stone-throwing young men tried to steal the cars of mourners outside the cemetery.
All flights to and from Tunisia were cancelled as the capital was shut down after the country's largest labour union called a general strike.
Tunisia has been rocked by clashes and strikes since Mr Belaid was shot dead outside his home on Wednesday, with violence in Tunis also leaving one policeman dead.
Another officer is said to be in a coma in hospital after being dragged from his car and beaten by protesters, who also set fire to a police station in the town of Gafsa.
The country is now embroiled in its worst crisis since the 2011 revolution that saw the overthrow of dictator Zine El Abidine Ben Ali, and triggered the Arab Spring.
Mr Belaid had accused the ruling Islamist Ennahda party of resorting to thugs to attack opposition rallies.
His family and allies have accused the party of complicity in his killing, sharply raising tensions ahead of the funeral.
More than a dozen offices of the Ennahda party were attacked overnight in towns around the country.
Schools, shops, banks and other institutions were all shuttered following the general strike called by the main labour union in protest over the assassination.
The decision by the army to provide security for the funeral procession may be key in preventing the situation from degenerating into violence as it remains a respected institution in the country, as opposed to the much-reviled police.
Several times in the past year the army has had to be called out in rioting towns to replace police forces that only seem to further antagonise protesters.
Tunisia's prime minister, Hemadi Jebali, offered to replace the government after Mr Belaid's killing in response to long-standing opposition demands.
However, his own ruling Islamist party rejected his decision - exposing divisions within the party itself between moderates and hardliners.
The Ministry of Interior has appealed for calm but the ministry building has been the focus of protests and has been ringed by several lawyers of iron barriers and barbed wire.