Norwegian authorities intend to boost security on the country’s energy infrastructure after the incident of gas leaks at parts of the Nord Stream gas pipeline.

Norway’s Petroleum Safety Authority (PSA) has said it had received warnings of sightings of drones of unknown origin flying near some North Sea oil rigs.

It noted: “The PSA has received a number of warnings/notifications from operator companies on the Norwegian Continental Shelf (NCS) concerning the observation of unidentified drones/aircraft close to offshore facilities.”

The authority has urged operators and vessel owners on the NCS to show “increased vigilance”.

In a statement released on behalf of the EU, the EU Foreign Policy chief Josep Borrell said: “All available information indicates those leaks are the result of a deliberate act.

“Any deliberate disruption of European energy infrastructure is utterly unacceptable and will be met with a robust and united response.”

Responding to various reports suggesting a “sabotage” behind the gas leaks in the major gas pipeline, Norway’s Energy Minister Terje Aasland said: “The government has decided to put measures in place to increase security at infrastructure sites, land terminals and platforms on the NCS.”