Nigeria's militant Islamist group Boko Haram has sworn allegiance to the "Islamic State" (IS). The group is the latest in a string of militant organizations to lend their support to the terrorist group.
In a tweet posted on Boko Haram's Twitter account on Saturday, Boko Haram's leader Abubakar Shekau purportedly pledged allegiance to IS, which currently rules a self-declared caliphate in parts of Iraq and Syria.
"We announce our allegiance to the caliph ... and will hear and obey in times of difficulty and prosperity," SITE Intelligence monitoring service quoted Boko Haram as saying in a video alleged to be from the Sunni group.
Boko Haram has captured several villages in Nigeria's northeast since launching military operations in 2009 and now controls an area roughly the size of Belgium.
On Saturday, bomb blasts in the northeastern Nigerian city of Maiduguri killed at least 50 people. They were the worst attacks there since Boko Haram militants tried to seize the town in two major assaults earlier this year.
In their six-year insurgency, the Islamist militants have killed more than 13,000 people, displaced more than 1.5 million, and abducted hundreds, including at least 200 schoolgirls from the Nigerian town of Chibok.
The group's rapid growth over the past year has alarmed Nigeria's neighbors, who reached an agreement in February to deploy a multinational force of some 8,700 soldiers in the region around Lake Chad.