The Tunisian Interior Ministry said the baby carrying the woman died on the spot and another young girl was injured.
Tunisian authorities say a woman has killed herself and her baby in a suicide bombing during a security operation in an inland mountainous province.
A statement from the Interior Ministry on Thursday night said two more militants had been killed in the operation.
In an operation, the Tunisian army found an armed group in the Mount Salom area of Kasserin province. The statement said they killed a suspected fighter, whose wife killed herself by activating an explosive belt.
Her baby was killed in her arms in the blast, and an older girl also survived the scene, the ministry said.
Authorities said they were taking refuge for the first time, citing the presence of a woman from one of the armed groups.
In the second operation, security forces killed a suspected leader of the Tunisian Jund al-Khilafah brigade in the Mount Maghila area, the statement said. The brigade pledged allegiance to the ISIS (ISIS) group and they are believed to have been behind several attacks in Tunisia in recent years.
Tunisia has since faced several attacks The 2011 revolutionDozens of security personnel, civilians and foreign tourists were killed.
It has maintained a state of emergency since a deadly 2015 attack on a presidential guard bus claimed by ISIL, renewing it twice a year.