By the mid-1970s , Arafat and his Fatah movement found themselves in a tenuous position . Arafat increasingly called for diplomacy , perhaps best symbolized by his Ten Point Program and his support for a UN Security Council resolution proposed in 1976 calling for a two-state settlement on the pre-1967 borders . But the Rejectionist Front denounced the calls for diplomacy , and a diplomatic solution was vetoed by the United States . In 1975 , the increasing tensions between Palestinian militants and Christian militias exploded into the Lebanese Civil War , involving all factions . On 20 January 1976 , the PLO took part in the Damour massacre in retaliation to the Karantina massacre . The PLO and Lebanese National Movement attacked the Christian town of Damour , killing 684 civilians and forcing the remainder of the town 's population to flee . In 1976 Syria joined the war by invading Lebanon , beginning the 29‑year Syrian occupation of Lebanon , and in 1978 Israel invaded South Lebanon in response to the Coastal Road Massacre , executed by Palestinian militants based in Lebanon
Coastal Road Massacre
Coastal Road massacre
Palestine Liberation Organization