The funerals of six policemen killed in clashes with gunmen in central Tunisia will take place on Thursday in the five different towns they hailed from, officials said.

The latest deadly violence, which erupted in the central Sidi Bouzid region on Wednesday and which the authorities blamed on "terrorists," comes a week after two policemen were killed in similar circumstances and amid rising anti-government sentiment within the security forces.

Five burials are expected in Sidi Bouzid and in Kasserine near the Algerian border, with the sixth funeral to be held in Kef in northwestern Tunisia.

A military source in Kasserine said the families of the victims were refusing the presence of government representatives at the funerals.

Dozens of police trade union activists drove Prime Minister Ali Larayedh and President Moncef Marzouki away from a memorial service last Friday for the two policemen killed in Beja, west of the capital.

Many in the security forces have vented anger at the inadequate resources for combatting militant groups.

Marzouki has declared three days of mourning for those killed on Wednesday.

The powerful UGTT trade union confederation has called a strike on Thursday in Sidi Bouzid, the poor central region where the uprising that toppled strongman Zine El Abidine Ben Ali in January 2011 first began.

Most of the schools in Kasserine were shut on Thursday morning, and a small protest was held in the town as the convoy carrying the body of the policeman to be buried in Kef passed through.

Wednesday's clash erupted as police were preparing to raid a house in the Sidi Ali Ben Aoun locality where the militants were holed up.

The government says one member of the "terrorist" group was killed and the security forces are pursuing the rest, without indicating how many there were.

Tunisia has been rocked by jihadist violence since Ben Ali's overthrow, with extremists blamed for the murder of two opposition MPs and a deadly attack on the US embassy last year.

The opposition has consistently accused the ruling Islamist party Ennahda of not doing enough to contain the extremists.