At least 11 people were killed in the early hours of Monday by gunmen in Port Harcourt, Rivers State.
The incident occurred in a residential area near the headquarters of the Nigerian Agip Oil Company in Port Harcourt.
However, eyewitnesses have put the casualty figure at 15.
Many of the injured persons are currently receiving treatment at some hospitals in the area.
The state’s Police Public Relations Officer, Nnamdi Omoni, a Deputy Superintendent of Police (DSP), who confirmed the incident, said more policemen have been deployed in the area to prevent breakdown of law and order.
Omoni said details of what led to the killings are still sketchy, adding that the state Police Commissioner, Zaki Ahmed and other senior police officers are on their way to the scene of the attack.