By Rafiu Ajakaye

LAGOS 

Nigerian army troops on Friday liberated Gwoza, a town that the Boko Haram militant group had used as the headquarters of its self-styled "Islamic caliphate" in northeastern Nigeria.

"Just this morning, the gallant troops of the Nigerian military in concerted and well-coordinated land and air operations liberated Gwoza, the headquarters of their so-called caliphate," defense spokesman Chris Olukolade said in a statement.

"This was preceded by successive [retreats] of terrorists from towns and villages leading to Gwoza, the main objective," he added.

According to the spokesman, several "terrorists" were killed and many detained in Gwoza, which is located in Nigeria's restive Borno State.

"A lot of arms and ammunition have been recovered and the administrative headquarters [of Boko Haram] was completely destroyed," Olukolade said.

"A massive cordon and search has commenced to locate any of the fleeing terrorists or hostages in their custody," he added.

Nigeria's defense headquarters said earlier on Twitter that army troops had captured the town, Boko Haram's last stronghold.

President Goodluck Jonathan predicted Wednesday that Gwoza would be recaptured from the militants by Friday.

Friday's announcement, which comes on the eve of March 28 presidential and parliamentary polls, means that most of the towns hitherto held by the militants have now been recaptured.

Nigeria is fighting a six-year Boko Haram insurgency that has claimed tens of thousands of lives and displaced over one million people from the northeastern region, where the militants have been the most ruthless.

Last year, Boko Haram went from attacking communities and planting bombs to capturing entire towns.

In mid-2014, the group declared a self-styled "Islamic caliphate" in areas seized in Nigeria's northeastern Adamawa, Borno and Yobe states.

Almost all areas hitherto controlled by the militants have since been liberated by the army, however, in operations that have also involved troops from neighboring Chad, Niger and Cameroon.