London - Nigeria's campaign against Islamist Boko Haram insurgents is being hampered by "cowards" within the armed forces, its presidential security adviser said in a rare public signal of unhappiness in the military high command with the effort.Boko Haram's bloody uprising to carve out a breakaway Islamic caliphate has taken much of Nigeria's northeast and poses the worst threat to Africa's most populous state and biggest energy producer and at least three of its neighbours.Boko Haram claimed a 3 January attack on the town of Baga that killed scores, possibly hundreds, of civilians and left the jihadists in control of the headquarters of a regional multinational force including troops from Niger, Chad and Cameroon.Nigerian soldiers fled the area after Baga was overrun. It was the latest in a recent series of Boko Haram successes that has cast doubt on the commitment of some in the Nigerian military, and 22 officers including a brigadier general are on trial over alleged sabotage in the war effort."Unfortunately we have a lot of cowards. We have people who use every excuse in this world not to fight," Sambo Dasuki, the top security adviser to President Goodluck Jonathan, told an audience at the Chatham House think-tank in London.But, he stressed, "there is no high-level conspiracy within the army not to end the insurgency."It is highly unusual for senior Nigerian security officials to comment on the counter-insurgency campaign, especially at the level of Dasuki, but it pointed to discontent within the security establishment with the conduct of the fight.Under-equippedDasuki denied that the army was under-equipped, as critics have asserted, calling this an "excuse." He said reinforcements had been sent in to retake Baga, something he hoped would be completed soon.But he said of the international troops stationed there: "That wasn't that much of a multinational task force, it was by name [only], because they were all supposed to be physically there," when in fact most were not.Dasuki added that the headquarters was being moved to the nearby Chadian capital N'Djamena, but that "Nigerians don't see what the use is" of the regional force.Analysts say regional mistrust has stalled efforts to fight Boko Haram, whose insurgency now transcends weakly policed borders.Dasuki also said Nigerian authorities should delay the 14 February presidential election to give organisers more time to distribute millions of biometric ID cards to voters.