Niger's defence ministry said Friday its troops killed 79 "terrorists" in operations last week that involved a foray into neighbouring Mali.
Troops from the army's anti-jihadist Almahaou operation began the search after they were attacked by an "armed terrorist group" in the western town of Tiloa on March 10, the ministry said.
It also came after at least 17 Nigerien soldiers were killed last month in Intagamey, another town in the vast western region of Tillaberi, one of several areas currently under a state of emergency due to jihadist attacks.
The pursuit, carried out by air and land forces, led to the Hamakat area of Mali, the hideout of the alleged perpetrator of the February 10 attack, the ministry said.
A security source contacted by AFP said the operation's extension into Mali was "unprecedented".
The ministry did not report any military casualties during the operation.
The attacks the army reported took place in Tillaberi, which straddles Burkina Faso and Mali -- two countries hit by jihadist insurgency.
The region has faced repeated attacks since 2017 by armed groups linked to Al-Qaeda and the Islamic State network.
In early March, Niger's armed forces Chief of Staff General Salifou Mody was received in Bamako by Mali's junta leader Colonel Assimi Goita.
Niger said they discussed cooperating on security along the two countries' more than 800-kilometre (500-mile) border.