Two women suicide bombers have killed 15 people, including themselves, in north-east Nigeria at a mosque in the compound of a government workers' housing estate and at another location there.

In a separate attack, the military said Boko Haram Islamic extremists attacked a rural military camp in north-east Yobe state overnight but were repelled by troops who killed at least 100 insurgents.

Army spokesman Colonel Sani Usman said seven troops died in the fighting and nine were injured in the village of Goniri.

Hours later, at around 6am local time when mosques are filled with the faithful for morning prayers, the suicide bombers struck in Damaturu, Yobe's commercial centre.

Residents blamed Boko Haram for the dawn attack on Buhari Housing Estate, apparently named after President Muhammadu Buhari.

The insurgents have stepped up attacks since Mr Buhari, briefly a military dictator 30 years ago, took office in May pledging to halt the insurgency.