The 'Action of Bjørn West' was a small clash between German forces and the Milorg military resistance organisation of the Norwegian forces (28 April/4 May 1945).

Located in Matrefjella in the Masfjorden area, Bjørn West was one of many bases operated by the Milorg military resistance organisation in German-occupied Norway. The base was under the direct control of the Norwegian high command in London, and its raison d'être was the establishment and support of a force that could operate behind German lines in the event of an Allied invasion of Norway. Should it come under German attack, the force was supposed either to withdraw to the mountains along the Sognefjorden, or to be evacuated by sea. The force received its supplies by sea as well as by air, and by the spring of 1945, totalled 255 men under the command of Kaptein Harald Risnes and Fredrik Kayser.

The Germans learned of the base’s existence early in 1945 and, wishing to establish a non-violent end in Norway to a war which Germany had effectively lost, Generalleutnant Johann de Boer, commander of the 280^th Division within the German occupation forces, attempted to contact the Norwegian resistance movement. This appears to have been an individual initiative, as General Franz Böhme, commander-in-chief in German-occupied Norway, ordered German troops to be prepared for battle. As de Boer tried to negotiate with the Norwegians, however, fighting broke out in Matrefjella between the German forces and the force at Bjørn West.

On 27 April, German forces and Gestapo personnel landed at Matre in Masfjorden, shortly followed by German warships in the support role. At about 04.00 in the morning of 28 April, the Germans attacked the base at Fossestølen, where Norwegian force repelled the smaller German force. The battles continued at Kringlebotn until the next day. There was hard fighting during the afternoon in the area to the north-west of Litlematrestølen, where 11 Norwegian soldiers repelled the Germans. Fighting broke out near Krokavatnet, to the north of Stordalen, on 1 May. Two days later, the Germans started crossing Klavefjellet toward Stordalen. After six days of battle, the Norwegians had lost six soldiers, while the Germans had suffered between 35 and 117 dead.

de Boer made it clear that the fighting had to stop, as otherwise there would be no reason to continue negotiations. The Norwegian forces had to withdraw, while he made sure the German attacks were halted. Bjørn West had received orders from London on 2 May to avoid further clashes, and the Norwegian force withdrew on 4 May.

The Germans in Norway capitulated on 9 May, five days after the fighting in Masfjorden had come to an end, and on same day, the Bjørn West force received order from the Norwegian government-in-exile to move to Bergen and assume control.