A police spokesman says at least 15 people have been killed by cattle rustlers who attacked a village in Nigeria's northwestern state of Zamfara.

Muhammad Shehu tells The Associated Press the victims were killed late Friday in Zakuna village in what appeared to be a reprisal attack. Shehu says the cattle rustlers had been repelled in an attack earlier in the day but regrouped.

Cattle rustlers have killed scores of people in Zamfara state since January amid growing tensions in the area.

Insecurity remains a major problem in Nigeria, Africa's most populous country. In the northeast, security forces continue to battle the Islamic extremist group Boko Haram, which still carries out deadly suicide bombings and mass abductions.