'Siskin' was a British operation by the Special Operations Executive to train resistance groups in the Sogn area of German-occupied Norway, especially at important power stations in readiness to undertake preventative action, and also to receive supplies and establish radio contact with the UK (October 1944/May 1945).

The four-man party, comprising M. Olsen, R. Ulstein, H. Svindseth and N. Fjeld, was delivered by sea and then trained groups in the relevant area and received supplies from the UK. Between 10 April and 1 May 1945, 35 tons of weapons and equipment were unloaded from submarine-chasers and by mid-April around 480 men had been organised in the Inner Sogn area alone. On 6 May Captain Wendelbø Lysne arrived to take over all forces in the area. Mobilisation of this force began on 8 May, and from the following day members of Nasjonal Samling (Norwegian Nazi party) and the Gestapo were disarmed and interned.