The 1975 Beirut bus massacre, also known as the Ain el-Rammaneh incident and the "Black Sunday", was the collective name given to a short series of armed clashes involving Phalangist and Palestinian elements in the streets of central Beirut, which is commonly presented as the spark that set off the Lebanese Civil War in the mid-1970s.

The Kataeb Regulatory Forces – KRF or Forces Régulatoires des Kataeb (FRK) in French, were the military wing of the right-wing Lebanese Christian Kataeb Party, otherwise known as the 'Phalange', from 1961 to 1977. The Kataeb militia, which fought in the early years of the Lebanese Civil War, was the predecessor of the Lebanese Forces. The militia was also involved in massacres against Palestinians in Beirut, Karantina and Tel al-Zaatar.