Fifty-three members of the security forces were killed in an attack by suspected jihadists in northern Burkina Faso, the army said on Tuesday.
Seventeen soldiers and 36 civilian volunteers for the army died on Monday while repelling an "attack," the army general staff said in a statement, adding several attackers had been "neutralised" in a counter-operation.
The West African country has been battling Islamist insurgents, some with links to al Qaeda and the Islamic State (IS) group, in its desert north since 2015.
Attacks have worsened this year, making the country the epicentre of a violent movement that has also engulfed poverty-stricken Mali and Niger, killing thousands and forcing millions from their homes.
Efforts by the army to retake areas have often led to an increase in the violence.
The latest fighting in Burkina Faso took place on Monday in Yatenga province, where the army has been trying to retake territory to allow displaced villagers to return home, the statement said. Military operations were still under way in the area.
Burkina Faso saw two military coups last year, triggered in part by insecurity. After the second one in October, Burkina Faso ordered French forces to leave amid growing tension between the junta and Paris.
The stated motive for the two coups was anger over the governments' failure to stem a jihadist insurgency that spilled over from neighbouring Mali.
But short on troops and supplies, Burkina Faso's junta has turned increasingly to volunteer defence forces to help. These armed civilians, who help police the rural north, are frequently caught up in deadly assaults, including in April when 34 were killed in a raid.
Since 2015, more than 16,000 people in Burkina Faso have died, according to an NGO monitor named ACLED, while more than two million people have fled their homes.
The junta has also looked to Russia to fill the void left by France's exit.
A Russian delegation held talks with Burkina Faso's interim president Ibrahim Traore last week at a meeting that included discussions on possible military cooperation.
(FRANCE 24 with AFP and Reuters)
