In August, Boko Haram declared an Islamic caliphate and now holds about 130 towns and villages.
The uprising killed about 10,000 people last year, compared to about 2,000 in the first four years, according to the U.S. Council on Foreign Relations.
MAIDUGURI, Nigeria (AP) — Nigerian troops Sunday repelled Islamic extremists who attacked from four fronts on Maiduguri, the biggest city in northeast Nigeria, with several civilians killed by aerial bombs and grenades and mortar shells on the ground.
Soldiers said hundreds of insurgents died.
Terrified residents fled homes shaking from five hours of heavy artillery fire and streamed in from the outskirts of the besieged city of 2 million, already crowded with another 200,000 refugees from the fighting.
In a separate attack, a suspected Boko Haram suicide bomber killed himself and eight others Sunday at the home of politician Sabo Garbu in Potiskum, in neighboring Yobe state, according to witness Abdullahi Mohammed.
Garbu is contesting a legislative seat in Feb. 14 balloting that includes a presidential election too close to call. Boko Haram denounces democracy.
For weeks Boko Haram has been closing in on Maiduguri, the group’s spiritual birthplace, and if it were able to plant its Islamic State-style flag there, even briefly, it would give them a major boost as the group loses ground in remoter areas, said Jacob Zenn, author of a book about the insurgents.
Its third attack in a week on Maiduguri came as Chadian forces launched a winning offensive, acting on an African Union directive for Nigeria’s neighbors to help fight the spreading Islamic uprising by Nigeria’s home-grown Boko Haram extremists.