On 6 June 1982, the Israeli Defense Forces, or IDF, moved across Israel's northern border into Lebanon. According to Prime Minister Menachem Begin and Defense Minister Ariel Sharon, "Operation Peace for Galilee" was intended to neutralize fighting units of the Palestine Liberation Organization (PLO) and to drive them far enough back from the Israeli border to prevent further harassment of Israel's northernmost settlements with rocket and artillery fire. The drive, Israel assured the U.S. government, would stop 40 kilometers, some 27 miles, into Lebanon.