Twenty-four soldiers have been killed in an attack by militants in eastern Mali, according to the country’s army.
Another 29 were also injured during a joint operation between troops from Mali and Niger in the GAO border region.
Mali’s army says 17 “terrorists” were killed and 100 suspects were being held in Tiloa, in Niger.
It comes weeks after 54 troops were killed in another attack one of the deadliest in the past decade.
Security forces have been struggling to contain the threat from Islamist Groups, some of which are linked to the so-called Islamic state or Al-Qaeda.
In recent months, Mali’s military has abandoned several outposts.