Geographical regions claimed by two or more countries involve special problems with visas, stamps, and border crossings.
In some cases, where the boundary is not demarcated, such as the Taiwan Strait, and Kashmir, involved parties define a line of control that serves as the "de facto" international border.
The term border dispute (or border conflict) applies only to cases where a limit territory bordering more than one state.
Occupied territories in general are regions distinct from the recognized territory of a sovereign state but which it controls, especially with military forces.
For more information, please see Territorial dispute@Wikipedia