Maiduguri - Suspected Islamist militants opened fire in a town in northeast Nigeria, killing at least 15 people, witnesses and a security source said.The attack on Monday night targeted Kautikari, near the Cameroon border, just 10km from the village of Chibok, where more than 200 schoolgirls were abducted in April. They remain captives."The were about twenty, well-armed. They came in four-wheel drive vehicles and some motorcycles. Initially, I thought they were soldiers," survivor Jonah Umaru said by telephone."The man running behind me was gunned down as I was fleeing. Afterwards, there were 15 people lying dead in the streets."Suspected Boko Haram gunmen kidnapped 172 women and children and killed 35 other people this month near the same area.Violence by Boko Haram, which is fighting to establish an Islamic state in Nigeria, has killed 10 340 people this year, according to a count by the Council on Foreign Relations last month.The five-year-old insurgency has also displaced more than a million people from the northeast. It is considered the gravest threat to the stability of Africa's biggest economy and top oil producer and its neighbours.Underscoring the regional threat posed by the group, Cameroon's army said it had killed at least 41 Boko Haram militants as it fought off a wave of attacks along its border with Nigeria over the weekend.Niger's Interior Minister Hassoumi Massaoudou told the National Assembly on Tuesday the country is ready to negotiate with Boko Haram but did not know who in the group to address."We want this war stopped. If we can talk with them to stop what's happening in Nigeria, why not," he said, adding that one objective would be to secure the release of the schoolgirls.Niger's southwestern Diffa region, which borders Nigeria's Borno State at the heart of the insurgency, has seen the arrival of more than 87 000 refugees since May of last year, according to Niger authorities.Instability in the northeast is likely to undermine efforts to hold Nigeria's presidential and other elections across the region in February.