Boko Haram has previously carried out attacks , including at churches , according to government officials . Militant Islamist group says it 's behind three attacks Sunday in cities of Kaduna and Kaduna . The attacks and retaliatory violence left three people dead , Abuja , Nigeria says . Safiya Akau says the bombings were retaliation for attacks on mosques .
Militant Islamist group says it 's behind three attacks Sunday in cities of Kaduna and Kaduna . The attacks and retaliatory violence left three people dead , Abuja , Nigeria says . Safiya Akau says the bombings were retaliation for attacks on mosques .