In 1976 Tel al-Zaatar refugee camp was home to more than 30,000 people; mostly Palestinians but also Lebanese. Initially established as a refugee camp to accommodate Palestinians displaced by the
1948 Palestinian expulsion and flight, the camp was administered by
UNRWA from 1952 until the
Cairo Agreement of 1969, which put the
Palestinian Liberation Organization (PLO) in charge of the camp. This attack led to the outbreak of the
Lebanese Civil War. Following a killing of five Phalangists in the Christian controlled area of Fanar on December 6, 1975, Maronite local militia captured hundreds of Muslims in East Beirut at random and massacred 150 to 200 of them in what became known as
Black Saturday. This led to more fighting between the rival factions. Tel al-Zaatar camp became a target of both the Phalangists and the
NLP Tigers. Christian militias such as the
Kataeb Regulatory Forces and the
Guardians of the Cedars began attacking Palestinian refugee camps shortly after the war began due to the PLO's support for Muslim and leftist factions. On January 18, they forcibly took control of the Karantina district and carried out the
Karantina Massacre. The Christian forces were initially leery of escalating PLO involvement in the war, but Karantina was inhabited partly by Lebanese Muslims and was located along the main road they needed to resupply their positions in Beirut, so it was considered a legitimate target. Tel al-Zaatar was immediately surrounded by 500 troops from the Kataeb Regulatory Forces, 500 from the NLP's armed wing (the
Tigers Militia), and 400 others from various other militias, namely the
Guardians of the Cedars. There were 1,500 armed PLO fighters inside the camp at the time. They were mostly affiliated with As-Sa'iqa and the Arab Liberation Front. There were also smaller groups of fighters from the
Popular Front for the Liberation of Palestine and the
Popular Front for the Liberation of Palestine – General Command. To complicate matters further, there were unaffiliated fighters present who fought under the PLO umbrella but did not support any one faction, mostly foreign
fedayeen. Factionalism within the camp contributed greatly to the success of the siege, as most of the As-Sa'iqa militants and As-Sa'iqa supporters left. == Siege and massacre ==