Following an assessment of the group's five-year uprising which has spread from Nigeria into neighboring African States, US intelligence officials concluded on Friday that the thousands of "hardcore" fighters do not currently pose a major threat to Nigerian oilfields in the south, which lend Nigeria the status of Africa's top oil producer.

The militants, who have carried out a string of massacres and kidnappings, were responsible for the deaths of some 10,000 people last year in their quest to create a "safe haven" in territory controlled by Boko Haram, which includes at least 30 towns and villages.

The group, which says it wants to establish an "Islamic state," has also produced videos praising the "Islamic State" militants who have taken over parts of Iraq and Syria.

Uphill struggle

The US officials, who spoke on condition of anonymity, also said on Friday that the militants are believed to be still holding about 300 schoolgirls who they kidnapped early in 2014. The girls are now thought to have been dispersed to multiple locations.

The intelligence officials added that Nigerian military forces were currently stretched in fighting the Boko Haram insurgents, as well as by their involvement in international peacekeeping forces.

Military forces in neighboring Cameroon, Chad and Niger, where the Boko Haram group has spread its attacks, have, however, been increasing their active role in combating the group.

"It remains to be seen how much tactical prowess [Boko Haram] have" in fighting regular military forces, one US official said.

Ahead of the Nigerian election period, Boko Haram attacks are expected to continue following a mixed pattern of small-scale and larger attacks which have been seen in recent months.

ksb/bw (Reuters, AFP)