In pictures: Fighting for Nigeria's oil

Mr Dokubu-Asari's supporters do not just rely on weapons - they also claim to have supernatural powers.

This man says that the leaf tied to his head protects him from machetes and bullets. Others carry their leaves in their pockets, or hidden under their hats.

The Ijaw strongly believe in their god of war - Egbisu.

If a person is killed despite carrying a charm, it is blamed on their having committed "impure deeds".