Militant group Boko Haram has said it has set up an Islamic state in the towns and villages it has seized in north-eastern Nigeria.
Boko Haram leader Abubakar Shekau was speaking in a video released to congratulate his fighters for seizing the town of Gwoza earlier this month.
It is not clear if Mr Shekau has pledged allegiance to Islamic State, which controls parts of Iraq and Syria.
Nigeria's army has rejected the claim as "empty".
Thousands of people have been killed in north-eastern Nigeria since 2009, when Boko Haram began its insurgency.
Gwoza, which had 265,000 residents in the last census, is the biggest town under Boko Haram control.
It has raised its flags over the palace of the Emir of Gwoza, the town's traditional ruler, residents say.
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Video - The state of Nigerian governance and Boko Haram