A local official says armed men killed at least 13 farmers in an attack in north-central Nigeria. No group immediately claimed responsibility for the attack that occurred in the state of Niger on Wednesday. Akilu Isyaku, a local government official, told a radio station that local herders and kidnappers are suspected in the killings. North-central Nigeria has been plagued by fights for control over water and land resources between nomadic herders and rural farmers. The violence has killed hundreds in the region so far this year. The area is also known as a place of frequent kidnappings.