However, the day after State of Aden joined the federation the Muhammad al-Badr of the Yemenese monarchy was overthrown and civil war ensued between forces backed by Gamal Abdel Nasser such as the National Liberation Front (NLF) and monarchist forces backed by the Saudi Arabia and the United Kingdom. Internal disturbances continued and intensified, leading on 10 December 1963 to the Aden Emergency, when a state of emergency was declared in the largely dysfunctional Aden State.[1]