A territorial dispute or boundary dispute is a disagreement over the possession or control of land between two or more political entities. Territorial disputes are often related to the possession of natural resources such as rivers, fertile farmland, mineral or petroleum resources although the disputes can also be driven by culture, religion, and ethnic nationalism. Territorial disputes often result from vague and unclear language in a treaty that set up the original boundary. Territorial disputes are a major cause of wars and terrorism, as states often try to assert their sovereignty over a territory through invasion, and non-state entities try to influence the actions of politicians through terrorism. International law does not support the use of force by one state to annex the territory of another state. The UN Charter states, "All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations." In some cases in which the boundary is not demarcated, such as the Taiwan Strait, and Kashmir, the parties involved define a Line of Control, which serves as the de facto international border. The term border dispute (or border conflict) applies to cases in which a limited territory is disputed by two or more states, each contending state would publish its own maps to include the same region which would invariably lie along or adjacent to the recognised borders of the competing states, such as the Abyei region which is contested between South Sudan and the Sudan. With border conflicts, the existence of the rival state is not being challenged, such as the relationship between the People's Republic of China and the Republic of China or the relationship between North Korea and South Korea, but each state recognises the shape of the rival state only as not containing the claimed territory, in spite of who actually governs the land and how it is recognised in the international community.