A Norwegian safety regulator said it would open an investigation into the oil spill reported last week in the North Sea.

Norwegian energy company Statoil reported a release of about 250 barrels of oil during the transfer of products to the oil tanker, Hilda Knutsen. Loading of oil from the Statfjord A platform was halted after a sheen was reported, through work at the platform itself continued without interruption.

"The Petroleum Safety Authority has resolved to investigate this incident, in part to clarify the course of events and to identify the direct and underlying causes," the safety regulator said in a statement.

The regulator said the incident occurred between the Statfjord A and Statfjord B platforms in the North Sea.

In January 2014, Statoil shut down operations at the Statfjord C platform after emergency systems detected an oil leak. More than 250 crewmembers were evacuated to lifeboats but returned to their living quarters later in the day.

No injuries were reported. Statoil said the weather in the area at the time of the Stratfjord C incident was "harsh."

The entire Statfjord region is producing an average 80,000 barrels of oil per day.