The region has seen an upsurge in Islamist militant attacks in recent weeks, reigniting a grinding conflict over the last 16 years that has left more than 40,000 dead and displaced two million.

Governors from the states of Borno, Adamawa, Yobe, Gombe, Taraba and Bauchi met in the Yobe state capital Damaturu for the 11th North-East Governors Forum.

Taraba state governor Agbu Kefas said in a closing speech that he and colleagues were alarmed at the increase in insurgent activity.

"The forum... calls for the armed forces, other security agencies and community leaders to reappraise their strategy in the counter-insurgency onslaught in the region," he added.

Kefas said a "multidimensional approach" was needed to address the "root causes" of the unrest, with work on youth employment and training, better roads and education and poverty reduction.

Boko Haram, which originated in Borno, and its splinter group Islamic State West Africa Province (ISWAP) have lost ground to the Nigerian army but have recently become more active.

The pair have notably resolved disputes between them to focus on fighting outside forces.

They have also adapted their combat tactics, especially through the use of drones, improvised explosive devices and coordinated raids.

The Multinational Joint Task Force (MNJTF) tasked with fighting extremists in the Lake Chad region since 2013 has meanwhile been weakened after Niger's withdrawal in March, affecting cross-border patrols and intelligence sharing.

Another member, Chad, has likewise threatened to pull out.