Burkina Faso, like much of West Africa s Sahel region, faces an uphill battle to tackle extremist groups. AFP
It was the sixth attack of its kind in the landlocked West African nation in under two weeks.
"A military unit carrying out a security operation in the eastern region was attacked about 20 kilometres (12 miles) east of Natiaboani on Sunday," the army said in a statement.
Security sources had on Sunday given a provision toll of 12 dead.
"During the fighting 13 soldiers were unfortunately mortally wounded and eight others injured," the army said, adding that several attackers had also been killed.
The rural community of Natiaboani lies 60 kilometres (37 miles) south of Fada N'Gourma, the largest town in the Eastern Region that since 2018 has been regularly targeted by armed groups.
Fifteen youths were kidnapped during an attack on Friday in nearby Nagre, according to the country's information agency.
Violence has flared again in Burkina Faso after a period of relative calm after a military junta took power in January.
Disgruntled officers toppled elected president Roch Marc Christian Kabore after protests over his handling of the bloody insurgency.
About two dozen civilians and a similar number of policemen or soldiers have been killed over the last 10 days.
Burkina Faso has been struggling with jihadist attacks since 2015, when militants linked to Al-Qaeda and the Islamic State group began mounting cross-border raids from Mali.
The violence has killed more than 2,000 people and displaced at least 1.7 million, according to an AFP tally.