A suicide bomber blew himself on Wednesday on a beach in Tunisia's resort town of Sousse while security forces foiled another planned attack nearby, the interior ministry said.

"A man blew himself up on a beach in Sousse," ministry spokesman Mohamed Ali Laroui told Agence France Presse, adding that no one else was killed.

Tunisia's army launched a "huge" operation to track down jihadists in the central Sidi Bouzid region Tuesday, the defense ministry said, after militants killed six policemen in the area last week.

"A huge military operation was launched on Tuesday in the hills of Sidi Ali Ben Aoun," a district of the Sidi Bouzid region, ministry spokesman Taoufik Rahmouni said, quoted by the official TAP news agency.

A first plenary session of Tunisia's elected Assembly since the launch of all-party crisis talks was delayed on Tuesday with parliamentary groups reportedly at odds over an electoral commission.

The deputies were to have met at 9:30 am (0830 GMT) to examine amendments to a law setting up the commission but the session was postponed until 1430 GMT, the Constituent National Assembly said.

The heads of 21 political parties were to gather Monday to try to agree on a new prime minister to be named this week to form a cabinet of independents.

Following a months-long political crisis, the government led by the moderate Islamist movement Ennahda is to be replaced under a series of talks launched on Friday.

Eight members of an armed group have been arrested in connection with the deaths of six Tunisian policemen in a clash last week, the interior ministry announced.

It said in a statement late Sunday that anti-terrorism units of the national guard arrested "eight terrorist elements implicated in the recent events" in the Sidi Bouzid region of central Tunisia.

Tunisia's ruling Islamists were due to hold a second day of talks Saturday with the opposition on resolving a crippling political crisis that erupted when suspected jihadists killed an opposition MP three months ago.

The much-delayed national dialogue began on Friday after Prime Minister Ali Larayedh made a written commitment to resign and make way for a cabinet of independents headed by a new premier who is to be named within a week.

Tunisia's divided factions began hard-won negotiations Friday to end a protracted political crisis after Islamist premier Ali Larayedh managed to avert an opposition boycott by making a written pledge to resign.

The repeatedly delayed national dialogue aims to break months of deadlock between the Islamist-led government and the mainly secular opposition that has paralyzed Tunisia's political transition nearly three years after the January 2011 uprising.

Tunisian security forces found a car bomb "ready to explode" at the site of clashes with suspected jihadists that left six policemen dead, the interior ministry said Thursday.

"We seized weapons, explosives, two grenade belts and a car bomb containing three canisters ready to explode," ministry spokesman Mohamed Ali Aroui said, speaking on Tunisian radio.

One of Tunisia's main opposition parties on Thursday ruled out participating in negotiations to end months of political deadlock without the government giving a written promise that it will quit.

"Nidaa Tounes believes it is not feasible for the dialogue to begin... without a formal and written commitment by the government to resign," said the party headed by ex-premier Beji Caid Essebsi, who is an outspoken critic of ruling Islamist party Ennahda.

Protesters attacked an office of Tunisia's embattled ruling Islamist party in the town of Beja on Thursday, leaving five party members wounded, Ennahda official Abdessatar Amdouni told local radio, hours after an Ennahda office was torched in the town of Kef.

"Five people were wounded, including one who had a fractured leg and another who suffered face burns," Amdouni told Shems FM radio station.