The Economic Community of West African States Monitoring Group (ECOMOG) was a West African multilateral armed force established by the Economic Community of West African States (ECOWAS). ECOMOG was a formal arrangement for separate armies to work together. It was largely supported by personnel and resources of the Nigerian Armed Forces, with sub-battalion strength units contributed by other ECOWAS members — Ghana, Guinea, Sierra Leone, The Gambia, Liberia, Mali, Burkina Faso, Niger, and others.