The ceasefire, however, merely postponed a larger crisis. The Lebanese remained at odds, Syria refused to withdraw its missiles, and Israel chafed under the restrictions of the ceasefire, which allowed the PLO to strengthen itself and did not prevent terrorist attacks from the West Bank and Gaza Strip or against Israeli and Jewish targets in Europe. In London on June 3, 1982, Palestinian assailants shot Shlomo Argov, Israel’s ambassador to the United Kingdom. The Israel Defense Forces (IDF) invaded Lebanon on June 6.