It was gathered that over 26 persons were shot in the attack, 14 persons died on the spot, with 12 hospitalised.
Although, there are conflicting reports on the number of casualties, some sources disclosed that 14 persons died, others said it was 15, while many said 16.
The Rivers State Police Command described the incident as unfortunate, adding that the culprits must be smoked out and prosecuted.
Public Relations Officer of the Command, DSP Nnamdi Omoni, said the Police are aware of the incident, but noted that the number of casualties cannot be confirmed at the moment.
Omoni said: “I can confirm the incident, but at the moment we cannot confirm the conflicting number of casualties.
“The Deputy Commissioner of Police in charge of operation and other tactical heads have been mobilised there to restore peace.
“The Commissioner of Police (Ahmed Zaki) has launched a manhunt for the bandits to ensure they are arrested and prosecuted.
“When the DCP and the teams conclude their investigations, we will know the total number of people involved.”
It was gathered that the unknown gunmen had operated at two different locations, Kirigani and Oboh axis of Aligu of Omoku, in a coordinated attack.
The killers opened fire on Christians that were returning from different churches around 12: 20a.m., after successfully crossing over to the New Year, and killed the number of persons.
Meanwhile, Director-General of the Nigerian Maritime Administration and Safety Agency, NIMASA, Dr. Dakuku Peterside, has lamented the killings.
He said: “I sympathise with the families of the deceased, as this is another set of deaths in a local government area that was held hostage by cult groups claiming supremacy and allegedly enjoying support from some politicians.
“It is highly regrettable that while other parts of the state were in celebratory mood, the people of ONELGA were mourning the passing away of their beloved in the most gruesome manner.
“My heart goes to the people of ONELGA and the immediate families of the deceased. This is an act that must be condemned.
“The good people of Omoku have suffered enough and this has further dealt a blow on their sufferings.”