Norway's jagged Arctic coastline has regained its strategic importance since tensions between Russia and NATO members have spiked to levels not seen since the fall of the Soviet Union.

The rocky relations have led some to criticise the shutting down of Olavsvern Naval Base, a massive complex burrowed into a mountain near the northern town of Tromsoe, that has been closed since 2009.

Shuttering it was driven by the then seemingly reduced threat from Moscow and its massive Northern Fleet based on Russia's nearby Kola Peninsula.

"We sold the only base worthy of the name that we had up there. It's pure madness," former vice admiral Einar Skorgen, who commanded Norway's northern forces, told AFP.