Tunisian security forces arrested a suspect in the murder of opposition politician Mohamed Brahmi after a fierce gunbattle during an overnight raid on a militant hideout.
Brahimi was the second of two opposition politicians to have been assassinated last year by suspected jihadists as Islamist violence rocked the North African country.
The security forces "surrounded a house (near the capital Tunis) where a terrorist group had holed up. Following a sustained exchange of fire, four elements were arrested," interior ministry spokesman Mohamed Ali Aroui told AFP.
"Among them is Hmed el-Melki, alias 'Somali,' one of the elements implicated in the assassination of the martyr Mohamed Brahmi," he said, adding weapons were seized during the raid.
"The interior ministry stresses that it was a successful operation," the spokesman said without revealing the identities of the other suspects.
The announcement came after the government said Tuesday that the suspected Islamist assassin of opposition politician Chokri Belaid had been killed in a police raid.
Gunmen killed Belaid on 6 February and Brahmi on 25 July, both of them outside their homes.
Authorities blamed the murders on the Ansar Al-Sharia, a jihadist outfit accused of links to Al-Qaeda, but the group never claimed responsibility for those or any other attacks.
Belaid was a charismatic leftist politician and virulent critic of the Islamist party Ennahda then in power.
His murder triggered massive anti-government protests and a crisis from which Tunisia has only recently started to emerge.
The two political assassinations eventually forced Ennahda to relinquish power in January in the face of accusations from the mainly secular opposition that it had failed to tackle a surge of Islamist extremism since the Arab Spring revolution of 2011.
Ennahda won Tunisia's first free elections in October 2011, following the ouster of president Zine El-Abidine Ben Ali in an uprising.
Speaking before the police raid on Monday, Belaid's widow Basma Khalfaoui accused Ennahda of hiding key documents in the murder inquiry and said she was expecting strong measures from a government of independents that replaced the Islamist-led administration late last month.
"We don't know anything (about what really happened). All scenarios are possible," she told AFP.
Brahmi's widow, speaking yesterday during a rally marking the first anniversary of Belaid's funeral, accused the authorities of having "done everything to wipe out the traces of the crime".