A suicide bomber has attacked a church in northern Nigeria , killing at least two people and injuring 48, according to the Red Cross.Witnesses at the scene in the city of Bauchi said they heard a blast near St John's Church, possibly in a car park.Bauchi has often been targeted by the Islamist Boko Haram group, which wants to impose Sharia law across Nigeria.Sunday attacks on churches took place regularly earlier this year but had eased in recent months.Attacks in central and northern Nigeria blamed on Boko Haram have killed some 1,400 people since 2010.On 16 September, Nigerian security forces said they killed Boko Haram's spokesman Abu Qaqa in a gun battle.However, the group has not confirmed his death.