The Islamist militant group, Boko Haram, which is fighting a violent insurgency in northeast Nigeria, has about 4,000-6,000 "hardcore" fighters, U.S. intelligence officials said Friday.
In an assessment of the group, whose five-year uprising has included massacres and kidnappings and spread from Nigeria into neighboring states, the officials said they did not believe it posed a major threat to Nigeria's oil fields in the south.
The officials, who spoke on condition of anonymity, said the militants were believed to be still holding about 300 schoolgirls they kidnapped early last year and had dispersed them to multiple locations.