The Mobil Producing Nigeria on Monday began to clean the oil spill along the Atlantic coastline in Akwa Ibom.
The News Agency of Nigeria (NAN) reports that the spill, which occurred on Nov. 9 at the company's offshore platforms, discharged some barrels of crude into the Atlantic Ocean.
A statement from the company in Eket, Akwa Ibom, on Monday said more than 200 barrels of crude spilled, up from the 100 barrels it announced on Sunday.
The company added that the exact volume of oil would be determined at the end of its investigation.
The statement, signed by Mr Paul Arinze, the General Manager, Government and Public Affairs, said the firm regretted the spill and apologised for the inconveniences it caused the people.
"Mobil Producing Nigeria regrets this incident. Our teams are being mobilised to clean up the area.
"We apologise for the inconveniences that it has caused," the statement quotes Mark Ward, the Managing Director of the company as saying.
The company engaged 150 youths from its host community to cleanup of the shoreline in the next 10 days.