In the early hours of 15 March, Israeli forces crossed into southern Lebanon to wipe out PLO terrorist bases which served as staging area for attacks on Israel. The land forces were aided by the airforce and by naval units operating from the sea against PLO bases in Tyre and Sidon. Israel stressed that the objective was not retaliation for the raid on the buses but to protect Israel from incursion of terrorists. The Israeli forces would remain in Lebanon until 13 June 1978. Text of the IDF spokesman statement follows as well as a background paper on the aims of the operation:
IDF forces a short while ago began a mopping-up operation along the Lebanese border. The purpose of the operation is - to root out the terrorist bases near the border and to strike at their special bases from which terrorists set out on missions deep inside Israeli territory. It is not the IDF's intention to harm the population, the Lebanese army or the inter-Arab force, but only the terrorists and their helpers, in order to safeguard the life and security of the population of Israel.
The objective of the operation is not retaliation for the terrorists' crimes, for there can be no retaliation for the murder of innocent men, women and children - but to protect the state of Israel and its citizens from incursions of members of the Fatah and PLO, who use Lebanese territory in order to attack citizens of Israel.
IDF operation background paper.
The IDF operation of the night of 14 March 1978 against concentrations of terrorists in Southern Lebanon comes in response to a long series of acts of murder and sabotage carried out by the Palestinian terrorists which reached their peak with the murder strike of Saturday, 11 March 1978. In this last act, the brutal nature of which shocked the entire world, 33 innocent Israeli citizens were indiscriminately cut down in cold blood and another 78 were wounded, most of them seriously. Among the victims were 6 women and 13 children.
There can be no shadow of doubt that the terror organizations, in their attempt to present their disgusting acts of brutality and murder as a war of liberation, are deliberately and in pre-meditated fashion planning their strikes against civilian populations and are even priding themselves on this. Thus for example, Habib Tarzi, the PLO representative to the United Nations, announced on Monday, 13 March, in the U.N. centre that terror attacks like that perpetrated on Saturday Israel will continue. PLO leader Yasser Arafat also stated explicitly on the same day in Beirut that some of the members of the terrorist team (the reference being to the murderers who penetrated the Israeli coast on Saturday) are still operating on the main highway to Tel Aviv. In this context, it should be noted that the Israeli authorities, wanting to prevent any further continuation of Saturday's bloodshed, imposed curfew on an entire area populated by 300.000 people.
Further confirmation of these objectives was given by Fatah intelligence department head (and central committee member) Salah Hdlef - known as "Abu Iyad" - who said in an interview with "El-Arab" of Qattar on 13 March 1978 that there would shortly be further commando operations "In the style of the Tel Aviv operation." He even emphasized that these operations would be carried out "On the Northern shore of Falastin."
It is noteworthy that Lebanon has for some time served as the main "Hothouse" of the terror organizations. Israeli settlements have since the Yom Kippur war been bombarded 1,548 times by artillery. Katyushas and mortars - for the most part from Lebanese territory. In these attacks and in terror strikes resulting from penetrations from Lebanon, 108 Israeli citizens were killed - mostly women and children - and 221 were injured. The terrorists recently deepened their penetrations of Southern Lebanon and were reinforced by units of As-Aika (an organization operated by the Syrians). The number of terrorists at present in Southern Lebanon close to the Israeli frontier, is 5,000. They are housed and trained in bases and camps alongside civilian populations - this in the knowledge that the IDF is sensitive about harming civilian communities.
The IDF raid in the night of 14 March 1978, comes in order to guarantee the life and security of the residents of Israel to defend the state and its citizens, and to prevent the attacks of Fatah and P.L.O. members - who use Lebanese territory to attack the citizens of Israel.