Tunisia said security forces killed a “terror” suspect and separately foiled a political assassination that has plunged the country into crisis.

The announcements came after rival protests for and against the Islamist-led coalition government.

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 after Chokri Belaid was assassinated in February.

Officials have said the same gun was used in both killings and pointed the blame at jihadists.

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

He also called for jihadist militants 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.

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.

“One of the members of the group was eliminated in an exchange of fire, and four were arrested,” the ministry said in a statement.

On sunday, Interior Minister Lofti Ben Jeddou said the security forces had arrested Ezzedine Abdelaoui, who is suspected of involvement in Belaid’s murder, during the raid.

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, 140 kilometres south of Tunis, on Friday.

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

During this raid, a suspect in Brahmi’s murder, Lofti Ezzine, was apprehended, Jeddou said.

The minister also detailed other security operations, including the arrest of a man suspected of planning a suicide bombing and the apprehension of three “religious extremists” preparing an attack on a bank.