The Nigerian military said that multiple attacks had occurred at four southwestern entry points to the city of Maiduguri, which has been targeted by Boko Haram for the first time in several months. The city is considered to be the birthplace of the jihadist movement in Africa.

The attackers included a woman suicide bomber, who managed to kill one other person while injuring 13 in a crowded area. In another blast, two girls blew themselves up in the Buraburin neighborhood, killing several people. Civil servant Yunusa Abdullahi described the city as "under siege" during the insurgent operation, adding that some residents had also found undetonated bombs since, one of which reportedly went off later.

"We don't know how many of these bombs or these female suicide bombers were sneaked into Maiduguri last night," he told the Associated Press news agency.

The attack appeared to challenge President Muhammadu Buhari's declaration earlier in December, saying that Boko Haram had "technically" been defeated with only smaller battles remaining. He had previously vowed to beat the militant group by the end of 2015.

Detailed chronology of events

The assault reportedly started with a group of militants firing indiscriminately from the back of three trucks in the outlying village of Dawari. A local reported that in the ensuing gun fight between government soldiers and the insurgents, a woman detonated herself amid fleeing people.

Shortly thereafter, a rocket-propelled grenade exploded, setting grass-thatched huts on fire, with a second woman blowing herself up among crowds trying to make an escape from the flames. A soldier told the Associated Press on condition of anonymity that insurgents had fired further rocket-propelled grenades into a total of four residential areas on the outskirts of the city. He also explained that many people got caught in the crossfire between Boko Haram fighters and government troops.

Later on, three suicide bombers reportedly blew themselves up at a home near Bakassi Estate, killing at least 18 people, another soldier told the Associated Press.

Another blast occurred at a mosque, when locals tried to defuse a bomb which then detonated. Reuters news agency reported that about 20 people perished in the incident.

PR Nigeria, an agency that disseminates government news, claimed that despite the devastating attacks, Nigerian troops had "intercepted and destroyed" 10 suicide bombers and repelled the attackers.

Violence spills over into Cameroon

Two female suicide bombers also blew themselves up in the Far North region of Cameroon. However, there were no other deaths. Another bomber died and two people were wounded in a separate incident in Tolkomari village, a local official said.

About 20,000 people have been killed in Nigeria and hundreds of others elsewhere as Boko Haram insurgents have carried their conflict across borders not only into Cameroon, which has suffered several attacks, but also to Niger and Chad.

ss/se (AP, Reuters, epd)