NSCDC Commandant in the state, Mr Desmond Agu, confirmed the incident in Yenagoa on Sunday and said that the command had recovered the remains.
He said the operatives were on a surveillance duty at Ogbobiri community in Southern Ijaw Local Government Area and were attacked while returning.
Agu, who described the incident as unfortunate, restated the commitment of his command to protect critical assets of the government against sabotage.
The commandant said that the pirates would not go unpunished, and commended his men for rising to the occasion.
According to him, the command is determined and motivated to deal with criminals.
A source at the NSCDC command, said that the officers were deployed to oil-bearing communities in the state following the activities of militants in the area.
The source said the incident happened on Friday at about 11.15 p.m., adding that the gunmen also suffered casualties.