The leak occurred on Monday.

The National Oil Spills Detection and Response Agency (NOSDRA) has confirmed an oil leak from the Nembe Oilfields operated by Aiteo Eastern Exploration and Production Limited at Nembe in Bayelsa State.

Solomon Ukponevi, head of NOSDRA's field office in Yenagoa, confirmed the development to the News Agency of Nigeria (NAN) on Wednesday in Yenagoa.

He said the oil firm reported the incident to the agency on Tuesday.

He explained that the agency had deployed its officials to the spill site to ascertain the cause and volume of crude oil discharged to the environment.

On the extent of the pollution, Mr Ukponevi said the Joint Investigative Visit (JIV) scheduled for Wednesday would determine the area, among other details.

"I will not be able to provide details until staff deployed for the JIV return from the fields, but I can tell you that Aiteo has reported the spill, and investigation is underway," he said.

NAN learnt that the leak occurred Monday at a section of the 97-kilometre Nembe Creek Trunk line (NCTL) that fed the Bonny Oil Export Terminal in Rivers.

Following persistent vandalism on the oil export line with the capacity to evacuate 180,000 barrels of crude daily, Aiteo resorted to using barges to convey crude from the Nembe fields.

The barges transport crude from onshore oil wells to a Floating Production Storage and Offloading (FPSO) vessel from which Aiteo exports the Nembe Crude blend to crude tankers.

The management of Aiteo has yet to respond to the incident.