Palestinian insurgency in South Lebanon peaked in the early 1970s, as Lebanon was used as a base to launch attacks on northern Israel and airplane hijacking campaigns worldwide, which drew Israeli retaliation. During the Lebanese Civil War, Palestinian militants continued to launch attacks against Israel while also battling opponents within Lebanon. In 1978, the Coastal Road massacre led to the Israeli full-scale invasion known as Operation Litani. Israeli forces, however, quickly withdrew from Lebanon, and the attacks against Israel resumed. In 1982, following an assassination attempt on one of its diplomats by Palestinians, the Israeli government decided to take sides in the Lebanese Civil War and the 1982 Lebanon War commenced. The initial results for Israel were successful. Most Palestinian militants were defeated within several weeks, Beirut was captured, and the PLO headquarters were evacuated to Tunisia in June by Yasser Arafat's decision. However, Israeli intervention in the civil war also led to unforeseen results, including small-scale conflict between Israel and Syria. By 1985, Israel withdrew to a 10 km occupied a strip of South Lebanon, while the low-intensity conflict with Shia militants escalated.