Leaders from five African nations are in Paris for a summit with officials from the US, France and Britain in the hope of co-ordinating a strategy against Boko Haram, the extremist group that abducted more than 200 Nigerian girls.

France, which has negotiated the freedom of a priest and a French family who had been abducted by Boko Haram, called the summit to share intelligence and work to find the kidnapped girls.

Officials have said there will be no Western military operation and Nigeria has only reluctantly accepted outside help.

Nigerian President Goodluck Jonathan cancelled a trip on Friday to the town where the girls were seized, apparently due to security concerns.

The militants, who claim to be fighting a holy war in Nigeria, move freely across the border into neighbouring Cameroon, where a Chinese company’s camp came under attack on Friday.

Boko Haram has offered to exchange the 276 girls who remain captive for jailed insurgents, and threaten otherwise to sell the the girls into slavery.

Signs are growing that some Nigerian troops are near mutiny, complaining they are overwhelmed and outgunned by Boko Haram insurgents.

Soldiers have told the Associated Press that some in the ranks actually fight alongside the group. Last year, Mr Jonathan said he suspected that Boko Haram members and sympathisers had infiltrated every level of his government and military, including the cabinet.

That complicates attempts to share intelligence. The US, France and Britain have all sent experts to help find the girls, but French and American officials have expressed concerns about how any information might be used.

The northeastern region where the girls were kidnapped has suffered five years of deadly assaults by Boko Haram. Thousands have been killed, including more than 1,500 civilians this year alone. Cameroon, which borders the region, has begun to take the threat more seriously after years of dismissing it as a Nigerian problem, French officials have said.