Training conducted in a clandestine fashion at the cell level by members of the terrorist group is considered what?

The scenario described revolves around training that occurs within a terrorist group, particularly at the cell level, which emphasizes the secretive and often hidden nature of such activities. This type of training is best categorized as internal training because it is conducted among members of the same group and focuses on enhancing skills or strategies relevant to their operations.

Internal training supports the operational integrity and cohesion of the group since it is designed to build on existing knowledge in a controlled environment. It underscores the importance of security and confidentiality in maintaining organizational effectiveness, especially in a context where exposure could lead to disruptions or external intervention. The description makes clear that this training is not intended for outsiders, aligning with the internal nature of the group's development and operational planning.

In contrast, other forms of training such as external training generally involve participants from outside the core group or entity, while public training would imply an open and accessible format, contrary to the confidentiality inherent in clandestine operations. Covert training, although similar in its secretive nature, typically implies secret operations conducted at a broader scale or in more diverse settings, rather than being focused on the internal dynamics of a specific group. Thus, internal training is the most fitting classification for such activities.