text: FM 7-100.1________________________________________________________________________________
  13-103. As pointed out, the OPFOR expects to commit infantry or mechanized
  infantry units through a secure beachhead to perform combat missions inland.
  However, these units may share in the assault landing role as well. If so, the
  OPFOR recognizes the need for at least a degree of special training. The
  ground force units may have attached naval infantry personnel to help over-
  come the special problems of an assault landing.
  Regional Operations
  13-104. Against a regional opponent, the OPFOR may be able to conduct
  amphibious landings as operational-level missions. In this case, a landing
  force of battalion or even brigade size, once landed, could conduct large-scale
  operations employing fixing, assault, and exploitation forces, as described in
  Chapter 3.
  13-105. The OPFOR’s naval infantry forces may be capable of forcible entry
  against regional opponents. Amphibious operations may entail the landing of
  a naval infantry battalion or brigade as the assault force. The exploitation
  force, consisting primarily of infantry or mechanized infantry troops, follows
  to exploit the opportunity created by the assault force.
  13-106. Even in regional operations, larger-scale amphibious landings are
  risky. Therefore, the OPFOR normally would not attempt them outside the
  range of land-based air cover and support. Linkup with a ground maneuver
  force should occur as quickly as possible.
  Transition Operations
  13-107. When an extraregional enemy has only early-entry forces deployed,
  OPFOR naval infantry forces may still be capable of forcible entry. Their in-
  sertion can complete the envelopment of a small enemy force. It could also
  help control further enemy deployment from the sea.
  Adaptive Operations
  13-108. The OPFOR does not have the capability to conduct opposed amphibious
  operations against a fully deployed extraregional force. It does, however, have
  the capability to transport up to a regular infantry or naval infantry battalion
  by sea, with limited amounts of supplies and heavy weapons. The unit is then
  landed unopposed at a predetermined site, away from the enemy’s main
  forces. In some cases, SPF or airborne troops may be inserted in lieu of using
  conventional infantry or naval infantry.
  13-109. During adaptive operations, amphibious operations typically comprise
  small-scale landings conducted in detachment strength. These operations
  include raids, ambushes, reconnaissance, and assaults, with detachment-
  strength actions being the norm. The raids and ambushes in this case would
  be small-scale actions conducted in a manner similar to those described for
  SPF earlier in this chapter, against isolated small enemy forces. Because of
  the extraregional force’s modern RISTA means, only shorter-range landings
  conducted during hours of darkness have a chance of achieving the surprise
  that is critical to success. Normally, linkup with friendly forces is planned to
  occur within hours after the landing.