Relations between Israel and its Arab neighbours were not normalized after the First Arab–Israeli War in 1948–1949. In 1956, Israel invaded Egypt, triggering the Suez Crisis. Among Israel's rationale for the invasion was its goal of reopening the Straits of Tiran, which had been closed by Egypt for all Israeli shipping since 1950. Israel was eventually forced to withdraw, but was guaranteed that the Straits would remain open. A peacekeeping contingent known as the United Nations Emergency Force (UNEF) was deployed along the Egypt–Israel border, but there was no demilitarization agreement between the two sides.