The Altmark Incident in Jossingfjord
Almost two months before German soldiers occupied the country, Jossingfjord was the scene of the first battle of the second world war in Norwegian territory.

Late in the evening of 16th February. the German tanker, „Altmark“, was boarded by a party of Marines from the Royal Navy destroyer, HMS „Cossack“, in Jossingfjord. On board the tanker were 299 captured British seamen, who were all freed during the dramatic rescue. Seven Germans
were killed in the action.
The „Altmark“ had sailed as an auxiliary with the German pocket battleship „Admiral Graf Spee“ in the South-Atlantic. Throughout the autumn of 1939, the „Admiral Graf Spee“ had posed a constant threat to the British merchant marine. Surviving seamen from the sunken British traders were now onboard the „Altmark“ en route to prison camps in Germany.
On 14th February the „Altmark“ entered the security of Norwegian territorial waters north of Trondheim fjord. The vessel gave every appearance of being an ordinary merchantman. Despite British protests the prisoners were not discovered by the Norwegian authorities, who allowed the vessel to sail with a pilot and escort southward down the coast.
Two days later the „Altmark“ was intereepted by Royal Navy vessels off Egersund. The British sought to capture the German tanker, which took shelter in Jessingfjord. The attack that followed was a clear violation of Norwegian sovereignty. Yet the Germans had deceived the Norwegian authorities by denying that the ship carried prisoners, and they had failed to make telegraphic contact with Bergen war harbour on passing as required.
The attack on the „Altmark“ took place on the personal Orders of Minister for the Navy, Winston Churchill. The matter received big headlines in the Norwegian and international press. It was later determined that the Norwegian authorities had conducted themselves by and large correctly during the over two days that the „Altmark“ was in Norwegian waters prior to the boarding.
But the lack of Norwegian resistance to the Royal Navy action was strongly criticised by Germany, and historians believe the event sharpened Germany’s interest in the Scandinavian countries. After the „Altmark Incident“ Germany could argue that Norway was incapable of defending her neutrality.

Source: Information board on site