Bodies of Palestinians killed in Sabra refugee camp in September 1982
With Egypt a treaty partner and Syria and Jordan quiet, Israel turned its attention to the Palestinian guerrillas. Many of them had grouped in Lebanon after being expelled from Jordan by King Hussein, and began attacking Israel from there.
The Palestinians, led by Yasser Arafat and his Palestine Liberation Organisation, would not recognise Israel and Israel would not support a Palestinian state.
In 1982, Prime Minister Begin launched "Operation Peace for Galilee", which was an invasion of Lebanon, taking the Israelis right up to and into Beirut.
Yasser Arafat and his fighters were forced to depart for Tunisia. But the operation went wrong for Israel. It was condemned by world - and much of its own - opinion when Christian fighters massacred hundreds of Palestinian civilians as the Israeli army stood by, and it failed to make a political agreement with the Christians stick. It pulled back to an enclave north of their border.