Nigerian police say a suicide bomber has killed at least two people and wounded more than 45 at a church in northern Bauchi state.

The attack took place on Sunday morning at Saint John's Catholic Church in Bauchi city, the state capital.

Authorities say the attacker was inside a vehicle loaded with explosives and detonated it during a security check outside the church.

There was no immediate claim of responsibility. The Islamist militant group known as Boko Haram has claimed responsibility for similar attacks across the north.

Boko Haram says it is fighting to establish a hardline form of Islamic law across Nigeria, Africa's most populous country.

The group does not recognize Nigeria's government or constitution.

Human Rights Watch says the group has been responsible for more than 1,000 deaths during the past three years.

Nigeria's population of 160 million people is divided roughly in half between a mainly Muslim north and predominantly Christian south.