Tunisia's party leaders met Friday to choose a new premier to be tasked with replacing an Islamist-led government and steering the country out of a months-long political crisis, mediators said.

The birthplace of the Arab Spring was plunged into turmoil after the assassination of a prominent opposition figure in July by suspected jihadists, with critics accusing the ruling Ennahda party, a moderate Islamist movement, of failing to curb extremists.

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 ruling Islamists and opposition were to begin hard-won negotiations on Wednesday to end months of political deadlock, with Prime Minister Ali Larayedh expected to announce his government's resignation.

Hundreds of opposition protesters gathered in central Tunis by early afternoon to keep up the pressure on the government, amid a heavy police presence, shouting slogans such as: "Government of traitors, resign!"

Tunisian security forces have killed "several terrorists" in an operation against an armed group suspected of an attack this week in which two policeman died, the interior ministry said Friday.

"Special forces from the interior ministry, the National Guard and the army took part in this operation. It began with air strikes and we are now in the terrestrial phase," ministry spokesman Mohamed Ali Aroui told Agence France Presse.

Tunisia's Islamist ruling party chief has said the government will not step down under pressure from the opposition, even as fresh protests were being readied Tuesday to demand just that.

And Prime Minister Ali Larayedh took a swipe at demonstrators, saying they were hampering efforts by security forces to root out gunmen linked to al-Qaida.

A roadside bomb went off as a national guard patrol passed south of Tunis early on Wednesday without causing any casualties or damage, a commander said.

The remote-controlled bomb struck at 12:45 am (23:45 GMT Tuesday) near Mhamdia, 30 kilometers (20 miles) from the capital, the town's guard commander Mohamed Jouhri told Shems-FM radio.

A bomb exploded near a police post in the port of Tunis on Saturday, damaging a police vehicle, the interior ministry said.

The blast, the first known attack of its kind against a security vehicle in Tunisia, came just hours before the funeral of assassinated opposition leader Mohamed Brahmi.

Tunisia faced a general strike Friday after gunmen shot dead a leading opposition figure in a killing that brought thousands of protesters onto the streets and sparked international condemnation.

Tunisia's national airline Tunisair cancelled all flights Friday.

Tunisian police arrested some 200 members of the hardline Islamist Ansar al-Sharia in weekend clashes that erupted after a ban on their congress, Prime Minister Ali Larayedh said in remarks published on Monday.

"Those who have been arrested number 200," Larayedh said at the Doha Forum in the Gulf state of Qatar, quoted by the Arabic daily al-Hayat.

Tunisian security forces deployed in strength on Saturday after Salafist movement Ansar al-Sharia called on its hardline Islamist supporters to defy a government ban on its annual congress.

There was a heavy police presence at tollbooths along the main highway from the capital to the central city of Kairouan where the Salafists have vowed to hold Sunday's gathering, Agence France Presse correspondents reported.