Terrorism is the systematic use of terror and at present, there is no internationally agreed definition of terrorism. Terrorism has been used by a broad array of political organizations in furthering their objectives; both right-wing and left-wing political parties, nationalistic, and religious groups, revolutionaries and ruling governments. The presence of non-state actors in widespread armed conflict has created controversy regarding the application of the laws of war. Terrorism is a growing problem in this unstable world.  A simple act of terrorism can cause tensions to break between two countries. Among the various potential threats are wars with neighboring countries, missile attacks on cities, biological and chemical terrorism, suicide bombings, and hostage taking. But terrorism is revealing itself in new forms in this modern world, such as massacres, hijackings, attacks on U.S. troops and hostage taking.