Four suicide bombers have killed at least 10 people and wounded many others in the Nigerian city of Maiduguri.The attackers, who included women, detonated their explosives in the Muna district, BBC reported on Wednesday citing the police.No group has said it was behind the attack. However, the Islamist militant group Boko Haram has carried out many attacks in Maiduguri, in Borno state.It frequently uses female suicide bombers to launch attacks.The first blast happened close to a group of people conducting evening prayer, killing seven, state official Bello Dambatta said.Another attacker detonated explosives inside a house and the other two blew themselves up before reaching their targets, he added.Boko Haram has been fighting to set up an Islamic state since 2009.Thousands of people have been killed and millions forced to leave their homes by Boko Haram violence in recent years.