"On Monday July 22, a unit of the defence and security forces exchanged fire with armed terrorist groups along the Bankilare-Tera route near the village of Foneko", it said in a communique read on state television, announcing a "preliminary toll" of 15 dead.

The ministry also said three soldiers were missing with 16 injured and hospitalised, adding that 21 "terrorists" had been killed in the clashes in the western region of Tillaberi.

The ministry went on to say the "prompt intervention of reinforcements from Tera" had forced the armed groups to retreat to the north.

The attack came almost exactly a year after a military coup which the army justified by deteriorating security in the country.

Twelve months on, armed groups notably from Islamic State and others loyal to Al-Qaeda, have continued to carry out attacks in the Tillaberi region, with bloody clashes over recent weeks leaving dozens dead on both sides.

Despite a large-scale rollout of troops and a promise to quadruple military numbers by 2030, civilians have also not been spared by the unrest.

However, exact victim tolls remain imprecise amid scant independent data.