When Frode Berg was a guard on the border near Kirkenes, Norway, in the 1990s and 2000s, relations with neighbouring Russia were so good that he would do joint patrols and go fishing with his colleagues from across the line. They drank vodka toasts after holding an annual cross-border ski race.

But in recent years this town of 3,500 on Norway's Arctic coast has found itself caught up in a geopolitical chess game between Nato and Russia. Mr Berg became the first pawn to be captured when he was arrested in Moscow and sentenced in April to 14 years in prison for espionage.

Located about 130 miles from Murmansk and the headquarters of Russia's northern fleet, sleepy Kirkenes has become the epicentre of a spy war with Russia—and Norwegians who have worked to develop cross-border trade and cultural exchanges are paying the price. One of them is even suing Norwegian intelligence over lost Russian business.

“If Norway has one real challenge regarding foreign policy, it's here,” said Kirkenes mayor Rune Rafaelson, a long-time friend of Mr Berg's who attended navy day celebrations in Murmansk last month. “It's not membership of the EU or making peace in Middle East. Here is the only real challenge, because we have an interesting and complex neighbour called Russia.”