text: FM 2-22.3_________________________________________________________________________________
  planning, the S2 must be aware of the capabilities and limitations of the
  various organic and attached collection systems as they apply to urban
  operations. As in all environments, commanders must assess the risk
  involved in the forward deployment of HUMINT assets.
  3-17. In urban operations, people (for example, detainees and civilians) are
  the preeminent source of information. HUMINT collection provides
  information not otherwise available through signals intelligence (SIGINT)
  and imagery intelligence (IMINT) such as threat and local population
  intentions. They collect information on, for example, floor plans, defensive
  plans, locations of combatants and noncombatants, including civilians in the
  buildings and surrounding neighborhoods, and other information. The
  collected information is passed directly to the individuals conducting the
  combat operation.
  3-18. In small-scale contingencies (SSCs) and in peacetime military
  engagements (PMEs), contact with local officials and populace by the
  HUMINT collectors can be a prime source of information about the local
  environment and is a vital component of intelligence support to force
  protection. During routine patrolling of urban areas it is often expedient to
  place a HUMINT collector with individual patrols. The key difference
  between urban and other operations, from major theater war (MTW) to PME,
  is the number of HUMINT collectors required. The need for HUMINT
  collectors is a function of population density. Whereas in a rural
  environment, a HUMINT team may be able to cover an area in excess of
  1,200 square kilometers; the same team in a dense urban environment may
  be able to cover only 10 square blocks or less.
  HUMINT COLLECTION ENVIRONMENTS
  HUMINT COLLECTION IN A PERMISSIVE ENVIRONMENT
  3-19. In a permissive environment, HCTs normally travel throughout their
  specific AOR as separate teams or as part of a larger reconnaissance team.
  HUMINT collectors may frequently make direct contact with the individual,
  view the activity, or visit the area that is the subject of the ISR effort. They
  normally use debriefing and elicitation to obtain first-hand information from
  local civilians and officials as their primary collection techniques. Additional
  information can be obtained from exploitation of open-source material such
  as newspapers, television, and other media. The priority requirements in this
  environment are normally linked to force protection. HCTs should establish
  liaison and casual source contacts throughout their AOIR. Reporting is
  normally via IIRs, although SALUTE reports are used for critical time-
  sensitive reporting. Even in a permissive environment, the HUMINT
  collector conducts the majority of his collection through the debriefing of
  individuals who have first-hand knowledge of the information they are
  reporting.