It said the child she was carrying died on the spot and another small girl was wounded on Thursday as the woman detonated the belt in the remote Mount Selloum area of Kasserine near the Algerian border, a known jihadist hideout.
National guard and army units the same day "eliminated" Hamdi Dhouib, a senior member of the outlawed Jund al-Khalifa, which is linked to the Islamic State (IS) group, in Mount Mghila, also in Kasserine, the ministry said in a statement.
Tunisia faced several jihadist attacks after its 2011 revolution, with dozens of security personnel, civilians and foreign tourists killed.
It has kept in place a state of emergency, renewed twice-yearly, since a deadly 2015 attack on a presidential guard bus claimed by IS.
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