In the early 1970s, tension along the Israel-Lebanon border increased, especially after the relocation of Palestinian armed elements from Jordan to Lebanon. Palestinian commando operations against Israel and Israeli reprisals against Palestinian bases in Lebanon intensified. On 11 March 1978, a commando attack in Israel resulted in many dead and wounded among the Israeli population; the Palestine Liberation Organization (PLO) claimed responsibility for that raid. In response, Israeli forces invaded Lebanon on the night of 14/15 March, and in a few days occupied the entire southern part of the country except for the city of Tyre and its surrounding area.
On 15 March 1978, the Lebanese Government submitted a strong protest to the Security Council against the Israeli invasion, stating that it had no connection with the Palestinian commando operation. On 19 March the Security Council adopted resolutions 425 (1978) and 426 (1978), in which it called upon Israel immediately to cease its military action and withdraw its forces from all Lebanese territory. It also decided on the immediate establishment of UNIFIL. The first UNIFIL troops arrived in the area on 23 March 1978.
In June 1982, Israel invaded Lebanon again. For three years, UNIFIL remained behind the Israeli lines, with its role limited to providing protection and humanitarian assistance to the local population to the extent possible. In 1985, Israel carried out a partial withdrawal, but it retained control of an area in southern Lebanon manned by the Israel Defense Forces (IDF) and by Lebanese de facto forces (DFF), the so-called "South Lebanon Army".
Although UNIFIL has been prevented from fulfilling its mandate, its contribution to stability in the region and the protection it has been able to provide to the local population remained important. The Force has recently been streamlined in order to achieve savings without affecting its operational effectiveness. The mandate has so far been renewed every six months. UNIFIL's current mandate was most recently extended to 31 July 1999 by Security Council resolution 1223(1999) of 28 January 1999.
As of May 31, 1999, UNIFIL had 4,500 troops; supported by international and locally recruited civilian staff. Military personnel were contributed by Fiji, Finland, France, Ghana, India, Ireland, Italy, Nepal, Poland. UNIFIL suffered 227 fatalities as of 31 December 1998.
On 17 April 2000, the Secretary-General received formal notification from the Government of Israel that it would withdraw its forces from Lebanon by July 2000 "in full accordance with Security Council resolutions 425 (1978) and 426 (1978)". He was further informed that in so doing the Government of Israel intended "to cooperate fully with the United Nations". The Secretary-General informed the Security Council of this notification on the same day, stating that he had initiated preparations to enable the United Nations to carry out its responsibilities under those resolutions. On 20 April, the Council endorsed the Secretary-General's decision to initiate those preparations.
As a first step, the Secretary-General sent his Special Envoy, Terje Roed-Larsen (Norway), together with the Force Commander of UNIFIL and a team of experts, to meet with the Governments of Israel and Lebanon and concerned Member States in the region, including Egypt, Jordan and the Syrian Arab Republic. The delegation also met with the PLO and the League of Arab States. During the mission, United Nations cartographic, legal and military experts examined the technical issues that would need to be addressed in the context of the implementation of resolution 425 (1978). Parallel to that mission, which took place between 26 April and 9 May 2000, the Secretary-General consulted with interested Member States, including those contributing troops to UNIFIL.
Starting on 16 May, much sooner than anticipated, IDF/DFF began to vacate its positions, amid exchange of fire. Beginning on 21 May, large crowds of Lebanese, accompanied by armed elements, entered villages in the Israeli-controlled area, and IDF/DFF vacated their position in great haste. At the same time, a large number of the de facto forces, together with their families, crossed into Israel. Others surrendered to the Lebanese authorities. Within a few days, those forces had completely disbanded. On 25 May, the Government of Israel notified the Secretary-General that Israel had redeployed its forces in compliance with Security Council resolutions 425 (1978) and 426 (1978).
UNIFIL continued to function in close cooperation with those authorities and no longer exercised any control over the area of operation. The Lebanese Government, however, still did not deploy its personnel down to the Blue Line.
UNIFIL focused on the remaining part of its mandate: the restoration of international peace and security, the report continued. Pending a comprehensive peace, UNIFIL sought at least to maintain the ceasefire along the Blue Line, through patrols and observation from fixed positions and close contact with the parties, with a view to correcting violations and preventing the escalation of incidents. The Secretary-General believed that the need for the United Nations to perform such functions would continue to exist in the foreseeable future.
In 2005, the resumption of military measures, for which Hezbollah took credit, asserting its claimed prerogative to resist Israeli occupation of Lebanese territory by force, was disturbing, the Secretary-General said in a report. The United Nations had made abundantly clear that no violations of the Blue Line were acceptable. The continually asserted position of the Government of Lebanon that the Blue Line was not valid in the Shab'a farms area was not compatible with Security Council resolutions. The Council has recognized the Blue Line as valid for purposes of confirming Israel 's withdrawal pursuant to resolution 425 (1978). The Government of Lebanon should heed the Council's repeated calls for the parties to respect the Blue Line in its entirety.
The Secretary-General said that the 2005 rocket-firing incidents perpetrated by individuals allegedly affiliated with Palestinian militant factions demonstrated the volatility of the sector. Importantly, none of the incidents resulted in a military escalation, and for this the parties and UNIFIL deserved credit. Nevertheless, this type of incidents presented a great risk to stability in the area. The Lebanese Government continued to exercise the capacity it had demonstrated thus far to exert its security authority through various activities of the Joint Security Force, including prompt responses to specific incidents. More needs to be done, however, to meet the Security Council's call for extended measures to ensure the return of effective governmental authority throughout the south, including through the deployment of additional Lebanese armed forces. Once again, the Secretary-General urged the Government to do its utmost to ensure calm and to exert full control over the use of force across its entire territory.
The escalation of hostilities in July 2006 between the IDF and Hezbollah has clearly affected operations of UNIFIL in the south. Under such circumstances, UNIFIL is doing its best to provide assistance within its limited capacities. On the humanitarian front, UNIFIL is ready to work in collaboration with the Lebanese government, but UNIFIL cannot replace the role of the Lebanese authorities in the area.
As of July 2006, 257 UNIFIL personnel have been killed in Lebanon, including 249 troops, 2 military observers, 2 international civilian staff, and 4 civilian staff members.