A strike by Norwegian oil workers could cause waves on the international oil market.
The pay dispute began on September 30th when talks between the Lederne union and the organisation representing oil companies collapsed.
The first production outages started on October 5th.
But operators say the latest strike news could knock out almost a quarter of the country's petroleum production by October 14th.
Norway is western Europe's biggest oil and gas producer.
And widening action raised the prospect of further price rises on the oil market.
Benchmark Brent crude traded up over 1.5% on Thursday.
And the concerns have kept Brent above $42 per barrel in recent days.
Norway's government can intervene if a strike is considered a national emergency.
But said it was up to the two sides to resolve their differences.
The union wants to match the pay and conditions of workers at onshore remote control rooms with those of offshore workers.
In 2012, the Norwegian government invoked its powers to end an oil industry conflict after 16 days.
Employers then had threatened a lockout of workers that would have shut down the country's entire oil and gas output.