Sometimes I get confused by my own research... The FSK generally recruits from the assault divers (MJK - Marinens Jegerkommando), the commandos (HJK - Hærens Jegerkommando) and paratroop units. The MJK and the HJK were formed in the 50s, partly based on the units who gained experience fighting alongside the British in WW2. The idea was to create saboteur units capable of independent operations behind enemy lines in the event of a Soviet invasion. Main source, still
www.mil.no.