Officials said more than 500 wounded people are trapped in the town of Fotokol, where fighting against Boko Haram began on Wednesday and continued throughout yesterday.
The latest bloodshed comes after Boko Haram warned other nations over uniting against it, and appears to be a direct result of Cameroon and Chad launching an offensive this week.
This new military involvement by other African nations in counter-insurgency campaigns in Nigeria stands to grow even bigger.
African leaders last week authorised a 7,500-strong force to fight Boko Haram.
“We consider Boko Haram to be a cancer, and if the international community does not focus its mind on this disease it will spread not only in Central Africa but other regions, all over the continent,” Cameroon’s information minister Issa Tchiroma Bakary said at the beginning of the three-day meeting in Yaounde.
Officials from the United States, France, Russia, Britain and the European Union are attending along with senior officials from the UN peacekeeping department.