Already in the evening of December 12, as part of the Operation "Jodła" (“Fir”) began the process of internment of persons perceived by the authorities as potential threat to the regime. Detentions were made by officers of the Militia and the Security Service, with accordance to the pre-prepared lists. Not only members of “Solidarity” were among the detainees. During Martial Law more than 10 000 persons have been interned. Some of them more than once.