blockade

Cutting-off of a place by hostile forces by land, sea, or air so as to prevent any movement to or fro, in order to compel a surrender without attack or to achieve some other political aim (for example, the Berlin blockade (1948) and Union blockade of Confederate ports during the American Civil War). Economic sanctions are sometimes used in an attempt to achieve the same effect.

During World War I Germany attempted to blockade Britain with intensive submarine warfare, and Britain attempted to blockade Germany. In 1990 a blockade by United Nations member countries was agreed in an attempt to force Iraq to withdraw from the invaded territory of Kuwait, but was superseded by open war. During the Yugoslavian civil war, international economic blockades were attempted against Serbia 1992–95, and by Serbia against the Bosnian Serbs during 1994–95.

No nation has the right to declare a blockade unless it has the power to enforce it, according to international law. The Declaration of London 1909 laid down that a blockade must not be extended beyond the coasts and ports belonging to or occupied by an enemy.