in 1982 Israel sent troops to Lebanon after the murder attempt on Shlomo Argov, the Israeli ambassador. This gave Israel a pretext to invade the south of Lebanon and the capital. This operation was called "Peace for Galilee". Its goal was to drive out the PLO fighters who established in the country. Though the murder attempt on Shlomo Argov was not perpetuated by the PLO, it gave to Israel the justification to attack Palestinian fighters in Lebanon. The Israeli army slowly advanced on Beirut where they joined their military forces with the Syrian forces already involved in the conflict and with the Lebanese Phalanges. They did not enter the capital until a cease-fire agreement was set up by the USA in September.