The government of Syria, although in theory a socialist regime, feared that a leftist victory and the installation of a radical government in Lebanon would undermine Syrian security and provide Israel an excuse to intervene in the area. After repeated diplomatic efforts failed to quell the Lebanese Civil War, on June 1, 1976, Syria intervened on the side of the Christians. In the following months, the Syrian presence grew to 27,000 troops. By November the Syrians had occupied most Muslim-held areas of Lebanon, including West Beirut and Tripoli. Most Muslim forces capitulated without firing a shot, overwhelmed by the Syrian show of force. In Sidon, however, Palestinian and leftist forces fought off the Syrians for nearly six months before relinquishing their stronghold.
For nearly the entire first year of the Civil War, the Phalangists and the PLO had made a mutual attempt to avoid combat, even as smaller Christian and Palestinian splinter groups clashed. The PLO tried to enhance its reputation and credibility by playing the role of a neutral mediator between the Lebanese left and the Christians. For its part, the Phalange Party avoided antagonizing the PLO because it feared that the Palestinians would intervene on the Muslim side. After Syria had subdued the Muslim threat, however, the Phalangists turned their full attention to the Palestinians.
The battle for Tall Zatar was the final showdown of the Lebanese Civil War. Tall Zatar was a Palestinian refugee camp situated on the Christian side of the Green Line where about 1,500 Palestinian guerrillas defended a civilian population of roughly 20,000 against several thousand Christian militiamen. The Christians were supported and advised in their siege by the Lebanese and Syrian armies; Israeli advisers were also present on the Christian side.
Because Tall Zatar was honeycombed with bunkers and tunnels, the PLO was able to defend the camp from persistent Christian attacks for about six months, despite a nearly constant barrage of artillery fire that took a large toll. On August 12 Christian forces finally overran the camp and massacred many of the several thousand civilians who had remained there.
Data as of December 1987