Tunisian police said its forces have shot a "terror" suspect and arrested four others in a dawn raid in the capital, Tunis, and separately foiled a political assassination like the one that has plunged the country into crisis. 

The announcements on Sunday came after rival protests for and against the Islamist-led coalition government, with the opposition demanding the resignation of the cabinet and the dissolution of the National Constituent Assembly.

The calls have mounted since the murder nearly two weeks ago of opposition MP Mohamed Brahmi, the second anti-government politician gunned down in Tunis since Chokri Belaid was assassinated in February.

Officials have said the same gun was used in both killings.

On Sunday, Prime Minister Ali Larayedh announced the first arrest of a suspect in the Belaid case, without elaborating.

He also called for armed fighters hiding out near the Algerian border to surrender.

"Hand over your arms, turn yourselves in to police, and then police and society will take that into account," he said, quoted by state news agency TAP.

'Key terror' suspects

The interior ministry, meanwhile, said the dawn raid targeted a house in the southern Tunis suburb of Ouardia where a group of "key terror" suspects was hiding.

Opposition groups have been holding protests outside
the Constituent Assembly in Tunis [Reuters]

"One of the members of the group was eliminated in an exchange of fire, and four were arrested," the ministry said in a statement that did not explain why the suspects were wanted.

Overnight, the ministry said police had foiled a new bid to assassinate a political figure and that two "very dangerous terrorists" had been arrested and guns and grenades seized.

The ministry did not identify the target of the plot but said it had taken place in Sousse, 140km south of Tunis, on Friday.

Police traded fire with gunmen after searching a house in the area, and a third suspect fled, it added.

The security force operations came as Tunisia's moderate Islamist Ennahda party was battling to defend its position as the head of a governing coalition after winning an October 2011 election.

Source: Al Jazeera and agencies