The Islamist extremist group Boko Haram has said it was behind the kidnapping of hundreds of school pupils in north-west Nigeria. If true the announcement represents a worrying sign that the jihadist group has extended its influence in the region. In a four-minute audio message, a man claiming to be Boko Haram leader, Abubakar Shekau, said the attack was against western education. Children as young as 10 years are among those missing. The governor of Katsina state has said 333 boys are still unaccounted for, but they’re in negotiations to rescue the pupils. The attack in President Muhammadu Buhari’s home state follows fierce criticism of the government’s record on security. In July, the radical Islamist group claimed in a video to have extended its influence to the north-west of the country. This year hundreds of people in the region have been killed in attacks by what authorities here call 'bandits'. Until now it’s been unclear whether these criminal groups had links with Boko Haram. However Ansaru, a splinter group affiliated with Al-Qaeda, is known to be active in the region. Boko Haram have waged a brutal insurgency since 2009, mostly focused in north-eastern Nigeria. The conflict has led to tens of thousands of deaths and displaced more than two million people.- BBC