The Finnish Army trained Sissi units to conduct long range reconnaissance patrols, gather intelligence from concealed observation posts, raid enemy installations (especially supply depots), conduct road side ambushes and pursue and destroy enemy special forces units. In wartime, an unspecified number of reservists were to be assigned to Sissi battalions and would deploy and operate as small groups up to company size. They were meant to either infiltrate through enemy lines to their rear, or stay behind and covertly operate against enemy forces in their area of responsibility even after regular friendly troops had been forced to retreat. Sissi battalions were part of Finnish Army "local troops", unlike the jäger and armored brigades meant for operational use.