France, April 9 -- Violence is surging across the country's mostly Muslim north, with at least 90 people killed by gunmen in several remote villages, according to an AFP tally of tolls given by local, humanitarian and church sources.

Africa's most populous country has been fighting a jihadist insurgency for 17 years, since Boko Haram's 2009 uprising, which has seen the emergence of powerful splinter groups including Islamic State West Africa Province (ISWAP).

In an overnight attack, unidentified jihadists overran a military base and torched vehicles in Benisheikh, about 75 kilometres from Borno state capital Maiduguri, an intelligence source told AFP.

"Unfortunately, the brigade commander, Brigadier General O.O. Braimah, lost his life,...