Abubakar Shekau made the announcement in late August and promised to extend their caliphate in the region.
The BBC reported:
Nigeria’s militant Islamist group Boko Haram has seized the key north-eastern town of Bama after fierce fighting with government forces, residents say.
Thousands of civilians have fled the town, along with soldiers, they added.
The military has not yet officially commented on the claim that it has lost control of Bama, the second biggest town in Borno state.
Last month, Boko Haram said it had established an Islamic state in areas it controls in north-eastern Nigeria.
It would be the biggest town under Boko Haram control.
Residents told BBC Hausa that Boko Haram captured Bama after heavy fighting on Sunday and Monday.
The jihadist Twitter accounts are celebrating the news.
— Sham O’File (@unseenfootage) September 2, 2014
ISIS fighters announced their 5 year plan to spread their caliphate into China and Spain in July.