Niger replaced two top military brass on Monday, four days after a jihadist assault on an army base left 89 dead in the biggest single loss in the country's history.
The new armed forces chief of staff is General Salifou Modi, who replaces General Ahmed Mohamed, the government said in a statement read on national radio.
The new head of the army is Brigadier General Seidou Bague, replacing Sidikou Issa.
The decision was made by a cabinet meeting shortly before Nigerien President Mahamadou Issoufou left for Pau, southwestern France, for a summit on the crisis in the Sahel.
It brings together a summit of the so-called G5 countries - Burkina Faso, Chad, Niger, Mali and Mauritania - with France, the former colonial power in the region, who is leading the fight against the insurgents.
According to UN figures, jihadist attacks in Burkina, Mali and Niger last year left 4 000 dead.
Niger declared three days of national mourning after the attack on Chinegodar camp in western Niger last Thursday.
It was carried out by attackers arriving in vehicles and on motorbikes.
The raid occurred in the same region, Tillaberi, where 71 soldiers were killed in December - a loss that deeply shocked the country.
Mohamed and Issa had been appointed to their jobs only in 2018.
Modi, 57, was a member of the Supreme Council for the Restoration for Democracy (CSRD), the official name of the military junta which staged a coup in 2010, returning the country to civilian rule after elections in 2011.