Blue Line ( Lebanon ) The Blue Line is a border demarcation between Lebanon and Israel published by the United Nations on 7 June 2000 for the purposes of determining whether Israel had fully withdrawn from Lebanon . At the same time , an extension , expressly not to be called the Blue Line nor considered the legally demarcated international boundary according to the UN , identified the Israeli withdrawal line between Lebanon and the Israeli - controlled Golan Heights . Background . On March 11 , 1978 , Palestine Liberation Organization ( PLO ) operatives , led by Dalal Mugrabi , carried out the Coastal Road massacre within Israel which resulted in the deaths of 37 Israelis , including 13 children . In response , Israeli forces invaded southern Lebanon from which the PLO operated regularly during the 1970s . Starting on the night of March 14 – 15 and culminating a few days later , Israel Defense Forces ( IDF ) forces occupied the entire southern part of the country except for the city of Tyre and its surrounding area . This operation is known in Israel as Operation Litani . On March 15 , 1978 , the Lebanese Government submitted a strong protest to the United Nations Security Council against the Israeli invasion , stating that it had no connection with the Palestinian operation . On March 19 , 1978 the Council adopted Resolution 425 , 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 the United Nations Interim Force in Lebanon ( UNIFIL ) . The first UNIFIL troops arrived in the area on March 23 , 1978 . Definition . The Blue Line is based on the deployment of the IDF prior to March 14 , 1978 . It should not be confused with the Green Line , established in 1949 , which is the armistice line of the 1948 Arab - Israeli War . The 1949 line is in turn the same as the 1923 Mandate Line which was the border between France and Britain ' s territory ( see : Treaty of Sèvres ) ; Lebanon is an ex - French mandate and Palestine / Israel an ex - British mandate . ( See League of Nations ) . The 1949 agreement stated that the line would follow the 1923 line . In 1923 38 boundary markers were placed along the 49 mile boundary and a detailed text description was published . The 2000 Blue Line differs in about a half dozen short stretches from the 1949 line , though never by more than 475 meters . Borders are usually negotiated between countries , and between 1950 and 1967 Israeli and Lebanese surveyors managed to complete 25 non - contiguous kilometers and mark ( but not sign ) another quarter of the international border . On April 17 , 2000 , when Israeli Prime Minister Ehud Barak announced that Israel would begin withdrawing its forces from Lebanon , the Lebanese government did not want to take part in marking the border . The UN thus conducted its own survey based on the line discussed in United Nations Security Council Resolution 425 . On May 25 , 2000 , the government of Israel notified the Secretary - General that Israel had redeployed its forces in compliance with Security Council resolutions 425 . From May 24 to June 7 , 2000 , the Special Envoy travelled to Israel , Lebanon and the Syria to follow up on the implementation of the Secretary - General ' s May 22 report . The United Nations cartographer and his team , assisted by UNIFIL , worked on the ground to identify a line to be adopted for the practical purposes of confirming the Israeli withdrawal . While it was agreed that this would not be a formal border demarcation , the aim was to identify a line on the ground closely conforming to the internationally recognized boundaries of Lebanon , based on the best available cartographic and other documentary evidence . On June 7 the completed map showing the withdrawal line was formally transmitted by the Force Commander of UNIFIL to his Lebanese and Israeli counterparts . Notwithstanding their reservations about the line , the Governments of Israel and Lebanon confirmed that identifying this line was solely the responsibility of the United Nations and that they would respect the line as identified . On June 8 , UNIFIL teams led by Lebanese Brig . General Imad Anka and Brig . General Amin Htait commenced the work of verifying the Israeli withdrawal behind the line . On June 16 , the Secretary - General reported to the Security Council that Israel had withdrawn its forces from Lebanon in accordance with resolution 425 ( 1978 ) and met the requirements defined in his report of May 22 , 2000 ; namely , Israel had completed the withdrawal in conformity with the line identified by the United Nations , South Lebanese Army militia had been dismantled , and all detainees held at Al - Khiam prison had been freed . The withdrawal line has been termed the Blue Line in all official UN communications since . Violations of the Blue line . 2000 Hezbollah cross - border raid . On October 7 , 2000 , three Israeli soldiers — Adi Avitan 22 , Staff Sgt . Benyamin Avraham 21 , and Staff Sgt . Omar Sawaid 27 — were abducted by Hezbollah forces . They were abducted while patrolling the southern ( Israeli ) side of the demarcation line recognized by the Secretary - General and the Security Council as the Israeli deployment line The soldiers were killed either during the attack or in its immediate aftermath . 2006 Hezbollah cross - border raid . Hezbollah precipitated the 34 - day long 2006 Lebanon War when its militants fired rockets at Israeli border towns as a diversion for an anti - tank missile attack on two armored Humvee s patrolling the Israeli side of the border fence . Of the seven Israeli soldiers in the two jeeps , two were wounded , five were killed , and two soldiers were taken to Lebanon . Israel responded with massive airstrike s and artillery fire on targets in Lebanon and a ground invasion of southern Lebanon . Israeli violations of Lebanon ' s airspace . Following 2000 withdrawal , Lebanon ' s military authorities report Israeli jets have violated the UN resolution 1701 by entering the country ' s airspace and breaking sound barriers over several villages in southern parts of the nation . Lebanese troops have responded by firing at the Israeli jets with obsolete anti - aircraft weapons . Lebanese officials have filed over 1600 air space violations by Israel since the 2000 withdrawal . 2010 Israel – Lebanon border clash . On August 3 , 2010 , Lebanese Armed Forces soldiers opened fire on Israeli army soldiers performing tree - cutting maintenance work on the Israeli side of the Blue Line as confirmed by UNIFIL . One Israeli was killed by Lebanese army fire and three Lebanese died when the Israel Defense Forces ( IDF ) responded . Lebanese Information Minister Tarek Mitri stated despite the fact that Lebanon accepted earlier the Blue line " The area where the tree was to be cut yesterday . . . is south of the Blue Line but is Lebanese territory . " UNIFIL determined that the Israeli troops were on Israeli territory . 2011 Israeli - Lebanon border clash . On August 1 , 2011 , UNIFIL confirmed a border incident in which no one was hurt . Israel and Lebanon offered differing accounts of the incident . A Lebanese military official said Israeli troops crossed the Blue Line 30 meters into Lebanese territory , prompting Lebanese soldiers to fire warning shots and the Israeli troops to retreat and fire at Lebanese border posts . The Israeli military sources said their forces were within Israeli territory when they came under fire from across the border .