of representing their concerns. Less democratic regimes also feared the threat the refugees posed to their own rule, but Lebanon would prove too weak to maintain a crackdown. The Palestine Liberation Organization (PLO) recruited militants in Lebanon from among the families of Palestinian refugees who had left Israel in 1948. War over water and 1967 Six-Day War Despite sharing in the ongoing border tensions over water, Lebanon rejected calls by other Arab governments to participate in the 1967 Six-Day War. Militarily weak in the south, Lebanon could not afford conflict with Israel. Nevertheless, the loss of additional territory radicalized the Palestinians languishing in refugee camps hoping to return home. The additional influx of refugees turned Palestinian camps throughout the Middle East into centers of guerrilla activity. Timeline Rise of the PLO militants (1968–1975) The PLO, from its inception in 1964 by Ahmed Shukeri, began executing numerous terror attacks on Israeli civilians in attempt to fulfill its mission charter's vow to pursue in "the path of holy war (al-jihad)" until the establishment of a Palestinian State in place of the State of Israel. The series of attacks (such as the 1966 bombings in Romema, Jerusalem) drove the Israeli Defense Forces (IDF) to strike in return, instigating the long and still unresolved struggle between the PLO and the IDF. From 1968 onwards, the Palestine Liberation Organization (PLO) began conducting raids from Lebanon into Israel, and Israel began making retaliatory raids against Lebanese villages to encourage the Lebanese people to themselves deal with the fedayeen. After an Israeli airline was machine-gunned at Athens Airport, Israel raided the Beirut International Airport in retaliation, destroying 13 civilian aircraft. The unarmed citizenry could not expel the armed foreigners, while the Lebanese army was too weak militarily and politically. The Palestinian camps came under Palestinian control after a series of clashes in 1968 and 1969 between the Lebanese military and the emerging Palestinian guerrilla forces. In 1969 the Cairo Agreement guaranteed refugees the right to work, to form self-governing committees, and to engage in armed struggle. "The Palestinian resistance movement assumed daily management of the refugee camps, providing security as well as a wide variety of health, educational, and social services." On 8 May 1970, a PLO faction, called the Democratic Front for the Liberation of Palestine, (DFLP) crossed into Israel and carried out the Avivim school bus massacre. In 1970, the PLO attempted to overthrow a