"Provisional death toll 11 dead, 34 injured, 24 of them seriously. Serious material damage. Enemy unknown," the ministry said, adding later one of the wounded had died.
The gunmen's descent on the military camp in Nampala was earlier claimed by a group from the ethnic Peul community, calling themselves the National Alliance for the Protection of Peul Identity and Restoration of Justice (ANSIPRJ).
The group said it had killed eight troops and wounded 11 more, as well as making off with two trucks and five pick-up trucks.
Al-Akhbar, a Mauritanian news agency, reported that several soldiers had been taken hostage, and the base set alight.
However, several security sources in the region told AFP they doubted the veracity of the claim of responsibility as the group was only founded last month following inter-communal clashes in the area and lacked the means to mount an attack.