Oil spilled into the North Sea during the loading of a tanker at Norway's Statfjord Field on Oct. 8, operator Statoil ASA (STO) said.

The leak occurred at 6:30 GMT during the loading of oil to a tanker from the Statfjord A platform via a loading buoy, Statoil said.

Production at the platform was proceeding as normal, but loading of tankers has been suspended and it is unclear when it will resume, it added.

"We are currently focusing on determining the cause of the leak and how much oil leaked," a spokesman told Reuters.

"The leak has been located ... We have closed the oil that is going to this buoy and are now currently checking if there is any oil left in the hose or in the pipes."

The Norwegian oil safety regulator was unable to provide further details. The Statfjord A platform can store up to 1.3 million barrels of oil.

Statfjord is one of Norway's oldest producing fields in the North Sea. It produced 24,300 barrels per day in July, the latest available data from the Norwegian Petroleum Directorate showed. Statoil's partners at the field are ExxonMobil Corp. (XOM) and Centrica Plc.

Offshore