Gunmen opened fire on Muslim worshippers as they were leaving a mosque in northern Nigeria on Sunday, killing at least 20 people.
The attack happened in a remote village, in Kaduna state,
Abdullahi Muhammad, the traditional ruler, said it was most likely carried out by a criminal gang in reprisal for a recent exchange of gunfire between the village and vigilantes.
He said an armed group is operating from camps in the forest.
