United States, US, intelligence officials have said Boko Haram is “financially secure” from bank robberies, kidnappings and other sources and is able to go “toe-to-toe” with the Nigerian military.

The intelligence officials told reporters that the terrorists are flushed with cash and weapons after a string of battlefield advances. US however expressed optimism that the terror group could face a tougher fight with Nigeria's neighbours.

The US officials' comments came as Boko Haram suffered heavy losses after launching a major attack into Niger republic, for the first time, last Friday. The clashes involved troops from Niger as well as Chad, which has adopted a leading role in the fight against the group.

The officials also said Boko Haram has about 4,000-6,000 “hardcore” fighters – considerably less than some estimates which have put the group's size at up to 10,000. However, the group could soon face an unprecedented test on the battlefield against more capable forces from Cameroon, Chad and Niger, they added.

The military intervention of neighbouring powers “potentially can be a game changer in a positive way,” one intelligence official said. The officials, who spoke on condition of anonymity, said Boko Haram are believed to still be holding about 300 schoolgirls they kidnapped early last year and had dispersed them to multiple locations.

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 oilfields in the south