NIAMEY, Niger — Boko Haram staged an overnight assault on a border town in Niger, residents said Sunday, the second time the West African nation has come under attack by the Nigeria-based extremists since Friday. The attack on the town of Diffa began on Saturday night, and fighting between Boko Haram and Niger's army lasted until 5 a.m. toward the town's southern entrance before the extremists were forced to flee and calm was restored, Diffa resident Adam Boukar said. Officials could not immediately be reached to confirm residents' accounts or give casualty figures. The fight against Nigeria's Boko Haram has taken on an increasingly regional dimension in recent months, with the extremists staging attacks in both Cameroon and Niger last week alone. Nearly 100 people were killed and some 500 wounded in an attack on the town of Fotokol in Cameroon on Wednesday and Thursday that saw Boko Haram fighters raze mosques and churches and use civilians as human shields, Cameroon officials said. On Friday, Boko Haram reached into Niger, attacking Diffa and Bosso, another border town. Chad and Niger troops responded to the assault in Bosso, while Niger's army pushed Boko Haram out of Diffa, inflicting “heavy losses,” Niger Defense Minister Mahamadou Karijo said. All told, 109 Boko Haram fighters were killed during the response to the attacks, while four Niger soldiers were killed and 17 were wounded, Karijo said. The figures he provided could not be independently verified. On Saturday, regional and African Union officials meeting in Cameroon's capital, Yaounde, unveiled a proposal for a force of as many as 8,750 members to combat Boko Haram. The manpower would come from Nigeria and its four neighbors. Chad and Nigeria would each contribute 3,500 troops each, while Cameroon and Niger would contribute 750 each and Benin would contribute 250. Officials said they envisioned deploying the force as early as next month, though the effort could be delayed for lack of funds. The UN has so far promised logistical and technical support. — AP