A sleeper cell is a cell of sleeper agents that belongs to a large terrorist organization. The cell "sleeps" (lies dormant) inside a population until it decides to act.
Sleeper cells have risk assessment levels ranging from Low to Urgent and may or may not act on its own, collectively as a hive mind, or under instruction and when directed, can be directed at a local, regional, national or international level.
Low Risk cells would be disorganized, untrained, unsupported, dissafected individuals with no special skills, no special knowledge, no access and no training but some open source information collection and discussion interests that might lead to collective action. Appropriate surveillance might include data mining and filters.
Medium Risk cells would be semi-organized, paramilitary or military trained, peer supported, dissafected or criminal groups or gangs with some special skills, some special knowledge, some ability to gain access, some training and some covert source collection abilities plus a history of protesting or demonstrating against presumed grievances and/or, vandalism and/or petty crime which may have resulted in some prison gang contact with radical or extremist ideologies. Appropriate surveillance might incude data mining and behavioral analysis.
High Risk cells would be organized, military trained, funded and supported, ideological groups with special skills, special knowledge, opportunistic access, training, covert source collection abilities plus no history of protesting or demonstrating against presumed grievances. Appropriate surveillance might include total information awareness, communications and control surveillance and disruption, covert observation and premptive strike preparedness.
Urgent Risk cells would be self actualizing, covert military, well funded and supported, non ideological groups with a wide range of special skills, special knowledge, virtually unlimited inside access, elite training, sophisticated covert source collection abilities including counter surveillance skills, plus no history, or record of presence. An appropriate level of surveillance is impossible.
See also: Sleeper Agents