A ministry statement said the "ambush" occurred yesterday on the road linking Douentza and Gao in the central Mopti region.
Northern Mali fell under the control of Islamic extremists in 2012, prompting a French-led intervention that drove them from cities and towns.
Northern and central Mali remain unstable and attacks on security forces are common. The militant group Ansar Dine is especially active in central Mali.
Earlier this month, President Ibrahim Boubacar Keita removed Defense Minister Tieman Hubert Coulibaly from his post after militants briefly took over the town of Boni.