KADUNA, Nigeria — Twin suicide car bombs exploded Sunday at a church inside one of Nigeria’s top military bases, killing at least 11 people and wounding another 30 in an embarrassing attack showing the continued insecurity that haunts Africa’s most populous nation.

No one immediately claimed responsibility for the attacks, but suspicion fell on the radical Islamist sect known as Boko Haram, whose suicide bombers target Sunday worship services in what has become a weekly macabre routine in Nigeria.