DAMATURU, Nigeria -- Two women suicide bombers killed 15 people, including themselves, early Wednesday in northeast 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 northeast Yobe state overnight but were repulsed by troops who killed at least 100 insurgents. Army spokesman Col. Sani Usman said seven troops died in the fighting and nine were injured in the village of Goniri.

Hours later, around 6 a.m. when mosques are filled with the faithful performing early-morning prayers, the suicide bombers struck in Damaturu, Yobe's commercial center.

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"One of the suicide bombers gained entry into the mosque and detonated explosives and the other bomber was sighted roaming around the compound and (when) asked questions, she too detonated explosives," said resident Ibrahim Musa.

He said he counted 15 bodies and 12 wounded people rushed to the hospital in Damaturu, which has suffered dozens of attacks during the 6-year-old Islamic uprising.

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

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

On Sunday, Boko Haram claimed responsibility for multiple explosions that killed at least 15 people last week in Abuja, the federal capital in central Nigeria.

Most attacks take place in the northeast and have spilled over into neighboring countries that regularly suffer suicide bomb explosions and hit-and-run raids.

Amnesty International estimates 20,000 people have died in the insurgency.

Risk consultancy Verisk Maplecroft has recorded 3,770 civilian deaths this year linked to Boko Haram's uprising.