The Israeli army launched a massive military incursion into Lebanon in
the summer of 1982. Operation "Peace for Galilee" was intended to wipe
out Palestinian guerrilla bases near Israel's northern border, although
Defence Minister Ariel Sharon pushed all the way to Beirut and expelled
the PLO from the country.
The invasion began on 6 June, less than two months after the last
Israeli troops and civilians were pulled out of Sinai under the 1979
treaty with Egypt. The action was triggered by the attempt on the life
of Israeli ambassador to London Shlomo Argov by the dissident
Palestinian group Abu Nidal.
Israeli troops reached Beirut in August. A ceasefire agreement allowed
the departure of PLO fighters from Lebanon, leaving Palestinian refugee
camps defenceless.
As Israeli forces gathered around Beirut on 14 September, Bashir
Gemayel, leader of the Christian Phalange militia, was killed by a bomb
at his HQ in the capital. The following day, the Israeli army occupied
West Beirut.
From 16 to 18 September, the Phalangists - who were allied to Israel -
killed hundreds of Palestinians in the Sabra and Shatila refugee camps
as they were encircled by Israeli troops in one of the worst atrocities
of nearly a century of conflict in the Middle East. Mr Sharon resigned
from his post as defence minister after a 1983 Israeli inquiry
concluded that he had failed to act to prevent the massacre.