YOLA, Nigeria (Reuters) - Muslim cattle herders are suspected of killing four police officers in the northeastern Nigerian state of Adamawa, a police official said on Friday. The four officers were killed on Thursday night defending a village in the Numan region from the herdsmen, who attacked the settlement as a reprisal for an earlier deadly clash, said Othman Abubakar, a police spokesman for the state. In the earlier clash, unidentified attackers killed more than 30 cattle herders in Numan. Numan has recently become a flashpoint for clashes between the herders and Christian farmers, which occur frequently across broad swathes of Nigeria, as each group contests the other s rights to land for pasture and agriculture. 
Ethnic clash in Nigeria leaves four police officers dead: official