“I counted 26 corpses yesterday evening,” one of the residents, Dauda Illiya, said.
Most of the deaths occurred during the raid but cannon fire from the government jet also killed at least six civilians – four women and two children, residents said.
“The pilot was just spraying bullets anywhere … People were running here and there. Many people were injured from the bullets,” said a local man, Suleiman Haruna.
Nigeria’s defence headquarters in Abuja did not respond to a request for comment on the incident, but a security source in Borno State confirmed the deployment of the military plane.
The residents and the security source said 20 militants were killed by local vigilantes who fought back, but this could not be confirmed as witnesses said the raiders carried off their dead in their trucks.
Nigeria’s armed forces are facing a fierce offensive in the northeast by the Islamist group Boko Haram, whose marauding bands of fighters have stepped up attacks against towns and villages after kidnapping more than 200 schoolgirls in April.
That abduction triggered an international outcry and increased support from Western governments for President Goodluck Jonathan’s fight against Boko Haram, which has killed thousands and abducted hundreds since launching an uprising in 2009.
Boko Haram, whose name means “Western education is sinful”, says it wants to set up an Islamic state in Nigeria, whose population is split between Christians and Muslims.
With the abducted schoolgirls still missing three months after their kidnap, Jonathan faces criticism at home and abroad over the deteriorating security situation in Africa’s leading oil producer and biggest economy.
The militants who attacked Dille, which is not far from the Cameroon border, were believed to have come from Boko Haram’s Sambisa forest stronghold where at least some of the kidnapped girls are thought to be held.
On Monday, Jonathan promised that the missing 219 girls, snatched on April 14 from Chibok, also in Borno State, would soon return home, teenage Pakistani activist Malala Yousafzai said after meeting him.
Malala, who became a global celebrity after surviving being shot in the head by the Taliban for campaigning for girls’ education, was visiting Nigeria to support the international campaign for the release of the abducted Nigerian students.
Now considered the main security threat to Nigeria, the Boko Haram insurgency is growing bolder and authorities and military experts fear it is seeking to push its campaign of violence into the country’s more prosperous south.