Nigerian authorities have discovered 12 unidentified bodies in a village in the southern part of the country.

Officials in Nigeria's Rivers state said Friday the bodies were found in the village of Uni Ikata, which lies in the country's oil-rich southern delta region.

Nigerian police say the cause of death is not immediately clear, and there have been no reports of recent clashes in the area.

Portions of Nigeria's central region have experienced a recent increase in ethnic and religious violence.

The United Nations says fighting in the country's so-called middle-belt, which separates Nigeria's predominately Christian south from the mainly Muslim north, has killed up to 70 people since August.