The first months of his tenure were spent combating terrorism. On 30 May, the Japanese Red Army killed 25 civilians and wounded 71 more at an attack on Lod Airport, Israel's leading transportation hub (see: Lod Airport Massacre). On 5 September of that year, another group attacked Israeli athletes at the 1972 Summer Olympics in Munich. The attack became known as the Munich Massacre. In response to these attacks, Elazar ordered what was, until then, the largest strike against Palestinian bases in Syria and Lebanon. Three Syrian jets were downed, and dozens of fedayeen were killed in a heavy artillery barrage. In Operation Spring of Youth, which took place on the night of 9–10 April 1973, dozens more Palestinians, including several key Palestinian leaders, were assassinated in Beirut by the IDF.