Tunis (dpa) – Eight people have been arrested over recent attacks in Tunisia, judiciary spokesman Sufian al-Sulaiti said on Wednesday, confirming that the mastermind behind the bombings has died.

Security forces carried out raids and arrested eight people on suspicion of involvement in two back-to-back suicide attacks in the centre of the capital Tunis last week.

The attacks, claimed by the Islamic State extremist group, killed one policeman and injured eight people. One of the attackers was also killed.

The arrests led to the identification of the mastermind behind the attacks, al-Sultaiti said.

The suspect blew himself up with a suicide vest on Tuesday evening to evade capture, the Interior Ministry said in the capital's western neighbourhood of al-Intilqa.

The security forces also seized a weapons depot in central Tunis, the spokesman added.

On Tuesday, local media reported that the 23-year-old suspect detonated the vest after security forces surrounded him near a tram stop and that he died at the scene.

There were no further casualties, according to the Interior Ministry.

Authorities stepped up security measures in response to the attacks.

In recent years, Tunisia has witnessed a string of militant attacks, most of them claimed by the Islamic State.

The North African country is widely seen as the sole democratic success story of the 2010-11 Arab Spring uprisings, but it has struggled with an economic slowdown and social unrest.