KANO, Nigeria (AFP) - Boko Haram's leader said he has created an Islamic caliphate in a north-east Nigeria town seized by the insurgents earlier this month, in a video obtained by AFP on Sunday.
"Thanks be to Allah who gave victory to our brethren in (the town of) Gwoza and made it part of the Islamic caliphate," Abubakar Shekau said in the 52-minute video.
He declared that Gwoza, in Borno state, now has "nothing to do with Nigeria".
"By the grace of Allah we will not leave the town. We have come to stay," said Shekau, who has been designated a global terrorist by the United States and sanctioned by the UN Security Council.
The United Nations humanitarian office (OCHA) earlier this month confirmed reports that Gwoza was under rebel control.
Boko Haram is also believed to be in control of other areas near Gwoza in southern Borno, as well as large swathes of territory in northern Borno and at least one town in neighbouring Yobe state.
Mapping the precise areas which have fallen into Islamist hands is nearly impossible.
There are few humanitarian workers on the ground in the north-east, travel is dangerous and the region, which has been under a state of emergency since May of last year, has poor mobile phone coverage.
Experts have described Boko Haram's gains in recent weeks as unprecedented, saying the group was closer than ever to achieving its goal of carving out a strict Islamic state across northern Nigeria.
But many analysts believe the military has the capacity to reverse the insurgents' advance.
Soldiers this week refused to deploy to Gwoza without better weapons in an apparent mutiny.