The attack occurred Saturday during a burial in the Nganzai district, near the Borno state capital, Maiduguri, local government chairman Muhammed Bulama said.
Twenty-one people were initially killed during the burial ceremony, Bulama said. An additional 44 people were killed when villagers ran after the assailants, the official said.
At least 10 people were injured in the attack. Eight of them were critically wounded and were being treated at an area hospital, he said.
The group has bombed churches and mosques; kidnapped women and children; and assassinated politicians and religious leaders.