maiduguri nigeria nigeria army say repel attack monday suspect boko haram militants city center conflict islamist insurgency major general nicholas rogers head nigeria military operations boko haram tell reuters situation maiduguri northeast nigeria control give detail government say alert boko haram attack christmas period festivals christians muslims embassies regularly warn nationals cautious avoid public space time heavy gunfire hear molai area outskirts city monday even prompt residents flee district two residents officer local vigilante group say vigilante commander ask identify say group join effort repel attackers immediate report casualties immediate claim responsibility also immediately possible identify target assault boko haram past target place worship religious celebrations include attack church christmas mosques muslim festivals prayer time last major boko haram attack maiduguri mainly muslim city christian minority june group launch assault eve visit vice president yemi osinbajo president muhammadu buhari administration previously say boko haram almost defeat late attack show group continue ability stage hit-and-run raid prompt renew government push militants nigerian government approve release billion last week state oil fund help fight nigeria long-term plan corral civilians inside fortify garrison towns move effectively cede rural areas boko haram nigeria replace previous military commander fight boko haram half year post military source tell reuters follow series embarrass attack militants nigerian army say repel suspect boko haram militant attack