Concentration camp would still not be the most accurate word to describe the situation though. It is not a purpose built area, but an already existing area cordoned off for “containment”. There is literally a word for what you described. It’s called a Ghetto. That is their purpose. To act as a restricted containment area to box in and segregate a target population, usually for the aim of elimination from society, or preparation for extermination.

Hence my example of the Warsaw Ghetto in the first comment. An near identical situation to what is happening in Gaza.