Kano: A girl thought to be as young as seven killed herself and seven others in a suicide bombing in northeast Nigeria as President Goodluck Jonathan conceded his government had initially underrated the Islamist extremist group Boko Haram.

The attack on a market in the city of Potiskum, the commercial capital of Yobe state, was the latest in a string of suicide strikes in which children have been used. The initial death toll given by witnesses and hospital sources was six, the bomber and five others but medical sources at the state-run hospital in Potiskum said later two of those injured had also died. Previous attacks have been blamed on Boko Haram.