A witness says two bombs have exploded near a mosque at evening prayer time and killed at least 26 people in Nigeria's beleaguered northeastern city of Maiduguri.

Residents who heard the massive blasts across the city immediately blamed Boko Haram, the Islamic extremist group that began in Maiduguri.

Seven people were killed by twin suicide bombers on Wednesday in a suburb of Maiduguri, a city that has nearly as many residents as refugees from the 6-year-old Islamic uprising that has killed about 20,000 people.

A civilian defense fighter who helped evacuate victims says he counted 26 bodies and 25 wounded people at the scene of Thursday's blasts near a mosque in Mulai suburb. He spoke on condition of anonymity for fear of repercussions from the military.