A court in Tunisia has sentenced four people to death and two to life imprisonment for their role in the assassination of opposition leader Chokri Belaid 11 years ago.

The sentences were confirmed on Wednesday by the deputy public prosecutor of the anti-terror judicial division. A total of 23 people had been charged in connection with the murder, with sentences ranging from two to 120 years handed down to other defendants, with five acquitted.

Dozens of Belaid supporters had gathered near the court in Tunis since Tuesday night, raising slogans demanding justice.

Belaid was shot dead in his car outside his home on February 6, 2013. The secretary-general of the Democratic Patriots Party was a fierce critic of the then-ruling Islamist party Ennahdha, claiming it had turned a blind eye to violence perpetrated against secularists.

His funeral was one of the largest public outpourings of grief in Tunisian history, with an estimated one million people taking to the streets, leading to massive protests.