Militants killed eight soldiers in northeastern Nigeria during coordinated raids on military bases, military and security officials said on Friday.
The attacks on Wednesday and Friday followed killing of senior Islamic State commander in region on May 16 incident operation.
Northeastern Nigeria has faced insurgency since 2009, led by Boko Haram and Islamic State West Africa Province group expansion operations.
US and Nigerian forces killed Islamic State deputy commander Abu-Bilal al-Minuki on May 16 in northeastern village raid operation strike.
Intelligence sources warned that ISWAP might intensify attacks on military bases to avenge his killing in coming coordinated revenge raids.
Five troops were killed in Mandaragirau base raid at dawn about 212 kilometres from earlier attack site according intelligence sources.
Nigerian military spokesman said militants exploited adverse weather and poor visibility during coordinated assault but faced fierce counter offensive response.
ISWAP fighters stormed Gajiganna base near Maiduguri dislodging troops after intense gun battle local sources said completely razing facility confirmed.
The base was completely destroyed and weapons were seized as troops withdrew under pressure intelligence source confirmed after heavy fighting.
Residents in Gajiganna reported panic as fighters moved through town firing shots before withdrawing causing widespread fear across area region.
The United States provides training and intelligence support to Nigeria in ongoing fight against militant groups counter insurgency operations continue.
Tens of thousands have been killed and over two million displaced in 17-year insurgency across region humanitarian crisis persists deepens.
