The Islamic State group on Tuesday claimed responsibility for an attack on an Army base in western Niger on January 9 that killed more than 80 soldiers, affirmed the monitoring group SITE .
"Clashes took place, lasting for several hours, with light, medium, and heavy weapons, which led to killing 100 elements and wounding others," according to a message by the Islamic State's West Africa Province (ISWAP) translated by SITE.
"The mujahideen then returned to their positions," it said.
Niger on Sunday said 89 of its troops and 77 assailants died in the raid on the base at Chinegodar, a military station near the Malian frontier.
It was the biggest one-day loss in the history of Niger, an impoverished country in the heart of the Sahel area which is struggling with a mounting Islamist insurgency.
According to UN figures, jihadist attacks in Burkina, Mali and Niger last year left 4,000 dead.
The attack on Chinegodar was carried by highly mobile assailants who arrived in vehicles and on motorbikes.
It occurred in the same region, Tillaberi, where 71 soldiers were killed last month. The IS also claimed responsibility for that attack.
Niger declared three days of national mourning after the losses and carried out a top-rank military reshuffle, replacing the chief of the Armed Forces and the head of the Army.
On Monday, France and five partners in the Sahel – Burkina Faso, Chad, Mali and Mauritania as well as Niger – vowed to step up their efforts against the revolt.
France has a 4,500 military mission in the Sahel, to which 220 more soldiers will be sent to help train local forces, President Emmanuel Macron announced.
"The new element is the recognition that the situation is not good and that the strategy pursued so far is not working well," said Jean-Herve Jezequel, in charge of the Sahel at the International Crisis Group, speaking of Monday's summit organised by Macron with Sahel leaders in southern France.
President Macron has explicitly expressed concern about the United States' reaction, due to a possible significant reduction in troop numbers. "I hope to convince [US President Donald] Trump that the fight against terrorism is playing out in this region as well," he said.