Gunmen on Friday killed 15 people in multiple attacks in northwest Nigeria's Kaduna state, the latest violence in the volatile region, a government official said.
Northwest and central Nigeria have been terrorised by criminal gangs known locally as bandits who raid villages, stealing cattle, kidnapping for ransom and burning homes after looting supplies.
They launched separate attacks on four villages across three districts, killing 15 people and injuring several others, Samuel Aruwan, Kaduna state internal affairs commissioner said in a statement.
The gunmen raided Rafin Sarki village in Giwa district "with 11 locals confirmed killed" -- 10 men and a woman, he added.
Cibiya and Karamai villages in Kajuru district were also attacked, leaving two people dead and "several persons were left injured".
Aruwan said two more people were killed in Damari village in Birnin Gwari district.
"The Government is engaging the security forces on these developments and other fronts," he said.
Kaduna is one of the states worst hit by bandits in northern Nigeria.
The conflict is compounded by sometimes deadly clashes between nomadic cattle herders and local farmers over grazing and water rights, which have assumed ethnic and religious dimensions.
Nigerian President Muhammadu Buhari is under intense pressure to end the violence before he leaves office next year at the end of his eight-year tenure.
There have been growing concern over increasing alliances between bandits and jihadists from the northeast waging a 12-year insurgency to establish a caliphate.
In May, Kaduna state governor Nasiru El-Rufai admitted that jihadists from IS-affiliated Islamic West Africa Province (ISWAP) and its rival Ansaru -- linked to Al-Qaeda -- were setting up bases in the state, particularly in Birnin Gwari district.
This followed an attack on a train outside Kaduna in March, when gunmen killed 14 passengers and kidnapped dozens of others after blasting the rail line with dynamites and opening fire on coaches.
The government blamed the attack on jihadists with the complicity of bandits.