An EU Battlegroup (EU BG) is a military unit adhering to the Common Security and Defence Policy (CSDP) of the European Union (EU). Often based on contributions from a coalition of member states, each of the eighteen Battlegroups consists of a battalion-sized force (1,500 troops) reinforced with combat support elements. The groups rotate actively, so that two are ready for deployment at all times. The forces are under the direct control of the Council of the European Union.