In the late 1960s, and especially after the expulsion of the Palestinian militants from Jordan in Black September events in 1970–1971, Lebanon had become the base for PLO operations. Palestinian militant organizations relocated their headquarters to South Lebanon, and relying on the support in Palestinian refugee camps, waged a campaign of attacks on the Galilee and on Israeli and Jewish targets worldwide. Increasing penetration of Palestinians into Lebanese politics and Israeli retaliations gradually deteriorated the situation.