Armistice agreements which terminate conflict may divide a larger political and cultural unit into two smaller units. This may give rise to tensions and border incidents which are a threat to the international peace and security in the area. Where interaction across the boundary is inhibited, it may also be source of social and economic difficulty, particularly for families; and this is aggravated when the boundary cuts through a city (as in the case of Berlin). A different form of division may occur when two or more foreign powers take on joint responsibility for one territory as in the case of Andorra, the New Hebrides, and the Canton/Enderbury Islands.
Examples of this problem are: Federal Republic of Germany and the German Democratic Republic (now reunited after 45 years); North and South Korea; India, and West and East Pakistan (now Bangladesh); Yemen; and Cyprus.