Gunmen have killed at least 57 members of a local self-defence vigilante group in clashes in northwestern Nigeria, a security source and local residents said on Tuesday.
The attack was the latest involving heavily armed criminal gangs known locally as bandits, who raid and loot villages, steal cattle and carry out mass kidnappings for ransom across northwest Nigeria.
Police confirmed Monday's violence in Zuru district of Kebbi State, without giving a casualty figure.
But the security source said 57 bodies had been recovered while two local residents said 62 people were killed.
Local residents often form informal vigilante units, known as Yansakai, to protect villages from bandit raids, though some states banned them after they were accused of abuses and extra-judicial killings.
"There was an incident involving Yansakai and bandits which left several dead on both sides," Nafiu Abubakar, Kebbi state police spokesman, told AFP.
"We don't have a specific toll yet, we are still compiling fatality figures."
The bandits were fleeing ongoing military operations on their enclaves in neighbouring Niger state when they were intercepted by the vigilantes, who had been tipped off about their movements, Abubakar said.
Local resident Almu Sallami said the vigilantes had mobilized from different villages to take on a large convoy of heavily-armed bandits.
Northwest and central Nigeria are a hub of criminal gangs which maintain camps in Rugu forest, straddling Zamfara, Katsina, Kaduna and Niger states.
The bandits launch periodic attacks on villages in Kebbi state near the border with Zamfara and Niger states and withdraw to their camps, according to police.
Security experts have warned the gangs who are driven by financial motives are increasingly forging alliances with jihadists from the northeast waging a 12-year old Islamist insurgency.
Security forces say they have been bombarding and raiding forest hideouts while authorities last year also cut telecommunications in some northwest states in a bid to disrupt bandit communications.
In January, Nigeria's government labelled the criminal gangs as terrorist groups in a bid to bring tougher sanctions against the gunmen and their informants.
Criminal gangs in the northwest made international headlines last year when they raided a number of schools and kidnapped students in a bid to squeeze more ransom out of communities.
Nigeria's bandit violence has its roots in the clashes over land and resources between farmers and nomadic cattle herders in the northwest where tit-for-tat attacks have spiralled into broader criminality.
