Nigerian troops backed by air support repelled a coordinated assault by Islamist insurgents on ​a military base in the northeastern state of Borno, ‌killing at least 80 fighters, including senior commanders, the army said on Wednesday.

Boko Haram and Islamic State West Africa Province (ISWAP) fighters have intensified ​attacks on military bases in recent weeks in Borno, the ​epicentre of Nigeria's 17-year Islamist insurgency.

The Reuters Iran Briefing newsletter keeps you informed with the latest developments and analysis of the Iran war. Sign up here.

Wednesday's assault followed multiple ⁠suicide bombings on Monday in Maiduguri, the capital of Borno, ​that killed at least 23 and left more than 100 ​wounded. The attacks on the northeast's most heavily defended city suggested that the Islamic militant groups have shifted tactics to counter intense government operations against ​them.

The pre-dawn attack targeted an army position in Mallam ​Fatori near the border with neighbouring Niger, with insurgents advancing on foot ‌and ⁠deploying armed drones, military task force spokesperson Sani Uba said in a statement.

Troops had anticipated the assault and mounted what Uba described as an "offensive-defensive" response, beating back the attack with ground ​fire and ​air support.

Nigeria's air ⁠force carried out precision strikes, while allied Nigerien jets hit retreating insurgents. Four soldiers were ​wounded and evacuated for treatment, Uba said, adding ​that ⁠airstrike damage assessments were ongoing.

The military said three "high-profile" insurgent commanders were killed, though Reuters could not independently verify the claims.

Troops also ⁠recovered ​a large cache of weapons, including ​assault rifles, RPG launchers, machine guns, ammunition, improvised explosive devices, and armed-drone components, ​Uba said.