Fighters from the al-Qaeda-linked Islamist group Mujwa stand guard in Gao. 
Islamist militants, some with links to al-Qaeda and Islamic State, have been waging an insurgency in northern Burkina Faso since 2015. The worsening violence spurred soldiers last month to overthrow the government in the second coup this year.
"Members of the regiment responded valiantly to direct and indirect fire from the enemy, who came in large numbers," said the army statement, adding that the death toll was provisional.
It said that at least 18 of the attackers were also killed.
Air reinforcements have been deployed in the area to carry out relief and response operations, the army said.