EDITORS PLEASE NOTE: CONTAINS GRAPHIC CONTENT<br/> <br />Two female suicide bombers blew themselves up in this market in Maidugur, northeastern Nigeria.<br/> <br />Emergency services say more than 20 people were killed.<br/> <br />According to witnesses, a woman entered from behind the city's crowded market, and detonated a bomb. While people rushed to help the injured, there was a second explosion.<br/> <br />And while no one has claimed responsibility, suspicion has already fallen on the Islamist extremist group, Boko Haram.<br/> <br />The use of female suicide bombers has become a favorite tactic for the group, who are intensifying their attacks in northeast Nigeria where they hope to carve out their own, independent Islamic state.
