ISIS has claimed responsibility for a suicide bomb blast in the Tunisian capital earlier this week.
A wanted militant wearing an explosives belt blew himself up in Tunis on Tuesday after being surrounded by police, the government said, but there were no other casualties.
It was the third such incident within a week and came a few months ahead of an election and at the peak of a tourist season in which Tunisia is hoping for a record number of visitors.
Two suicide bombers blew themselves up in separate attacks on police in Tunis on June 27. ISIS militants claimed responsibility for both attacks.
A passerby wounded in one of the bombings has died of injuries, bringing the death toll to two.
Interior Ministry spokesman Sofiane Zaag announced the death on Radio Mosaique on Thursday.
A police officer was also killed in the June 27 attack. Several were wounded, and one remains hospitalized.