"The 45 bodies were found scattered in the bush. The bandits pursued residents who mobilised to defend the village after overpowering them," said a vigilante who asked not to be named for fear of reprisals.
"The dead included children abandoned by their parents during the attack" in the village of Gwaska, in Kaduna state.
"The attackers were obviously armed bandits from neighbouring Zamfara state who have been terrorising Birnin Gwari area," he added.
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The Kaduna state police chief, Austin Iwar, confirmed the attack, saying: "There was violence between the militias, who are very powerful, and bandits."
He could not break down the casualties, saying only: "For now all we know is that 12 people were buried yesterday and 33 today."
The vigilante said the bandits struck at about 2:30 pm (1330 GMT) Saturday and stayed for three hours before retreating to their base in the forest in Zamfara. "They burnt down many homes," he said.
The killings follow the death of 13 people in prolonged clashes between cattle thieves and local civilian militia in Zamfara last week.
The attacks underlined the diversity of Nigeria's security threats that persist because of an overstretched army and security forces.
Rural communities in Zamfara have been under siege for several years from cattle rustlers and kidnapping gangs, who have raided herding communities, killing, looting and burning homes.
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To defend themselves, villages and herdsmen form vigilante groups, but they too are often accused of extra-judicial killings, provoking a bloody cycle of retaliatory attacks.
Adding to the proliferation of violence due to these criminal groups, Nigeria is in the grip of a security crisis as nomadic herders and sedentary farmers fight over land in an increasingly bloody battle for resources.
Nigerian President Muhammadu Buhari has been criticised for failing to curb the violence, which is becoming a key election issue ahead of presidential polls in 2019.
The military and police are fighting Boko Haram jihadists in the north, militants and pirates in the oil-rich south, a simmering separatist movement in the east as well as the bloody conflict between herdsmen and farmers spanning the vast central region.
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