The attacks, near the airport in Maiduguri, the capital of Borno State, were the deadliest in months. They suggested the group’s enduring strength despite the Nigerian government’s assertions that Boko Haram had been severely weakened and President Muhammadu Buhari’s pledge to wipe out its last members within three months.
The four explosions detonated within 25 minutes on Sunday evening in an area called Gommari in Maiduguri. The targets included a railway crossing, a mosque, a video center where fans were watching a soccer match and a market where Muslims were buying sheep and other provision for the coming Eid al-Adha holiday.
“More than 100 have died so far,” Abba Mohammed Bashir Shuwa, an aide to Gov. Kashim Shettima of Borno, said in a telephone interview on Monday evening.
Mr. Shuwa said Boko Haram insurgents had taken advantage of the Muslim holiday week, during which many residents of surrounding villages gravitate to Maiduguri to shop.
“That’s what happened,” he said. “They melted among the villagers and came in as traders.”
Mr. Shuwa said that recent military gains had significantly weakened Boko Haram and that the attacks had been carried out by “remaining pockets that seek opportunities to strike.”
Col. Sani Usman, the army spokesman, said in a statement that the “attacks signify high level of desperation on the part of the Boko Haram terrorists.”
In staging the attacks during the holiday week, Boko Haram ensured that casualties would be high. Also, in keeping with the group’s long campaign of terrorizing the population with bombings, abductions and plundering, the attacks were certain to disrupt the state’s holiday celebrations.
Maiduguri is the epicenter of a protracted insurgency by Boko Haram, which was founded in that city more than a decade ago.
Marauding, kidnapping and pillaging by Boko Haram fighters have uprooted entire villages in Nigeria and more recently in neighboring Chad, Niger and Cameroon. Amnesty International has estimated that Boko Haram violence has left at least 17,000 people dead since 2009, when the insurgency began.
Boko Haram and regional leaders have been engaged in intensifying propaganda exchanges over the group’s strength.
Mr. Buhari asserted recently that military forces had gained the advantage against Boko Haram, recapturing territory and fracturing its leadership. Last month, Chad’s president, Idriss Déby, said Boko Haram’s leader, Abubakar Shekau, had been replaced, and Mr. Déby predicted that the group would be vanquished by year’s end.
Over the weekend, an audio message said to have been recorded by Mr. Shekau sought to rebut the assertions. “They are actually the ones whom we have driven away,” the voice said. “They are all liars.”
The authenticity of the message, distributed by jihadist websites, could not be verified.