An investigation into six bodies buried in shallow graves in Nigeria's Delta region was underway, local police said.

The bodies were exhumed by some people on Monday in Uwheru Kingdom, Ughelli North local government area of the Delta State, said Hafiz Inuwa, the state's police chief.

The six people were allegedly killed and buried after a clash among at least three local communities in Uwheru Kingdom occurred on Saturday, Inuwa said.

"It is the investigation that will tell us who killed them; who buried them; when they were buried, and who exhumed them."said Inuwa.

A team of security personnel and local people discovered the graves on Monday and exhumed the bodies, a witness has said.