Siege of Beirut The Siege of Beirut took place in the summer of 1982 , as part of the 1982 Lebanon War , which resulted from the breakdown of the cease - fire effected by the United Nations . The siege ended with the Palestinian Liberation Organization being forced out of Beirut and Lebanon . Historical setting . The PLO moved its primary base of operations to Beirut in the early 1970s , after Black September in Jordan . The presence of Palestinian forces was one of the main reasons that led to a Christian - Muslim conflict in Lebanon in 1975 – 1976 which ended with the occupation of Lebanon by peace - keeping forces from several Arab countries , including Syria . Over the next few years , the Syrians and the PLO gained power in Lebanon , surpassing the ability of the official Lebanese government to curtail or control their actions . Throughout this time , artillery and rocket attacks were launched against Israel . Israel bombed targets in Lebanon and in 1978 launched a military invasion in to Southern Lebanon codenamed " Operation Litani " . In 1978 , and again in 1981 and early 1982 , the United Nations sponsored a cease - fire , and Israeli troops were withdrawn . In 1982 Israel re - invaded Lebanon following the attempted assassination of its ambassador in London , despite being aware that the attack had been carried out by the Abu Nidal faction , which was at war with Arafat ' s PLO . The architect of the war , Ariel Sharon ( then Defence Minister ) , presented it to the Israeli government as a limited incursion into Southern Lebanon but took his troops to Beirut . The invasion was code - named " Operation Pines " or " Peace for Galilee " , and was intended to weaken or evict the PLO and impose Bashir Gemayel , head of the Christian Phalange party , as President of Lebanon in order to get Lebanon to sign a peace treaty with Israel and bring the country into Israel ' s sphere of influence . This plan failed when Gemayel was assassinated not long after being elected President by the Lebanese parliament under Israeli pressure . The Israeli forces invaded in a three - pronged attack . One group moved along the coastal road to Beirut , another aimed at cutting the main Beirut - Damascus road , and the third moved up along the Lebanon - Syria border , hoping to block Syrian reinforcements or interference . By the 11th of June , Israel had gained air superiority after shooting down a number of Syrian aircraft ; Syria called for a cease - fire , and the majority of PLO guerrillas fled Tyre , Sidon , and other areas for Beirut . The Siege . The ring around Beirut was closed by 13 June 1982 , 7 days after the start of Israeli invasion to Lebanon . PLO and part of Syrian forces were isolated in the city . Israel hoped to complete the siege as quickly as possible ; their goal all along in invading Lebanon was for a quick and decisive victory . In addition , the United States , through their representative Philip Habib , was pushing for peace negotiations ; the longer the siege took , the greater Arafat ' s bargaining power would be . At first Israelis thought that Christian Maronite forces would eradicate PLO quasi - government in Beirut , but it turned out that the Maronites were not prepared to undertake this task . For the IDF the capture of Beirut in street - to - street fighting would have involved unacceptable level of casualties . That is why the method chosen , was the combination of military pressure and psychological warfare to persuade the PLO that the only alternative to surrender was total annihilation . For seven weeks , Israel attacked the city by sea , air , and land , cutting off food & water supplies , disconnecting the electricity , and securing the airport and some southern suburbs , but for the most part coming no closer to their goals . As with most sieges , the population of the city , thousands of civilians , suffered alongside the PLO guerrillas . Israel was roundly accused of indiscriminately shelling the city in addition to the other measures taken to weaken the PLO . By the end of the first week of July 500 buildings had been destroyed by Israeli shells and bombs . On 14 of July Ariel Sharon and chief of staff Rafael Eitan obtained Prime Minister Begin ' s support for large scale operation for conquering of West Beirut in order to achieve the eviction of PLO . But the plan was rejected on 16 July by full Israeli cabinet , out of concern for heavy loss of life . Some parties threatened to leave the ruling coalition if the plan was adopted . At the end of July , with negotiations still deadlocked , the IDF intensified its attacks . Mossad , using their Phalangist contacts , sent Arab agents into Beirut with car bomb s in order to terrorize the Palestinians into submission and the Lebanese to increase pressure for their departure . Dozens of people died as a result of these bombings . Some of the Israeli agents were caught and ultimately confessed . Israeli Air Forces ( IAF ) intensified missions specifically designed to assassinate Palestinian leaders – Yassir Arafat , Abu Jihad and Salah Khalaf ( Abu Iyad ) . The IAF were assisted by agents with transmitters on the ground . But though a number of apartment houses were destroyed with hundreds of Palestinians and Lebanese killed or wounded , the leaders managed to evade bombings . On 10 of August , when American envoy Philip Habib submitted a draft agreement to Israel , defense minister Sharon , probably impatient with what he regarded American meddling , ordered a saturation bombing of Beirut , during which at least 300 people died . That bombing was followed by the protest to the Israeli government by President Ronald Reagan . In response , on 12 of August , the Israeli cabinet stripped Ariel Sharon of most of his powers , he was not allowed to order the use of air force , armored force and artillery without agreement of cabinet or prime - minister . During the siege , the Israelis secured several key locations in other parts of Lebanon , but did not manage to take the city before a peace agreement was finally implemented . Although Syria had agreed on 7 August , Israel , Lebanon , and the PLO finally agreed , with US mediation , on the 18th . On 21 August , 350 French paratroopers arrived in Beirut , followed by 800 US Marines and Italian Bersaglieri plus additional international peacekeepers ( for a total force of 2 , 130 ) to supervise the removal of the PLO , first by ship and then overland , to Tunisia , Yemen , Jordan , and Syria . Altogether 8500 PLO men were evacuated to Tunisia , and 2500 by land to other Arab countries . Results . In the end , Israel succeeded in ending the rocket attacks for a very short period , and routing the PLO from Lebanon , but failed to weaken the PLO overall . The siege also saw the insubordination and subsequent dismissal of the 211th Armor Brigade commander , Eli Geva , who refused to lead his forces into the city , arguing this would result in " the excessive killings of civilians . " Following the siege of Beirut , Arafat fled to Greece , and then to Tunis , establishing a new headquarters there . PLO " fedayeen " continued to operate out of Yemen , Jordan , Algeria , Iraq , and the Sudan , as well as within Israeli - controlled territory . International reaction . The siege of Beirut by Israeli military forces was highly controversial and was condemned even by Israel ' s traditional close ally , the United States , warning Israel that weaponry provided by the United States was only to be used for defensive purposes . The U . S . government at one point even considered threatening sanctions against Israel in order to stop Israel from launching an assault on West Beirut in August 1982 . The Soviet Union tried to pass a United Nations resolution calling for a worldwide arms embargo on Israel , which was vetoed by the U . S . Aftermath . Decades after the siege , the event was cited by Osama bin Laden as a major reason for the September 11 , 2001 attacks .