Tunisia was hit Thursday by fresh protests, clashes and strikes sparked by the assassination of outspoken opposition leader Chokri Belaid, as the ruling party broke ranks over how to defuse the crisis.

Tunisia was hit Thursday by fresh protests, clashes and strikes sparked by the assassination of outspoken opposition leader Chokri Belaid, as the ruling party broke ranks over how to defuse the crisis.

The country's main trade union called a general strike on Friday to coincide with the funeral of Belaid, a lawyer and vocal critic of the ruling Ennadha party who was shot dead outside his home by a lone gunman.

In the capital, police fired tear gas at demonstrators marching on the interior ministry to protest Belaid's assassination in broad daylight on Wednesday.

The protest march came despite a heavy deployment of police in Habib Bourguiba Avenue, epicenter of the 2011 uprising that toppled former president Zine El Abidine Ben Ali and where thousands had gathered Wednesday in scenes reminiscent of the revolt.

Clashes also erupted in Gafsa, in Tunisia's volatile central mining region, with protesters throwing petrol bombs at police who fired tear gas in response, correspondents said.

Thursday's unrest follows violence the day before that left one policeman dead in Tunis and saw protesters torch and ransack offices of the Ennahda party in a number of towns, including Gafsa.

Tunisian lawyers, judges and some teachers began a strike on Thursday while the General Union of Tunisian Workers (UGTT) announced on its website it had called a general strike on Friday.

Four opposition groups including Belaid's Popular Front bloc said they were pulling out of the National Constituent Assembly (NCA), elected in October 2011 but which has failed to draft a new constitution.

Belaid's family said his funeral will take place on Friday after the main weekly prayers. Hundreds gathered on Thursday outside his family home to pay their respects.