UNITED NATIONS - A staff member of a UN peacekeeping force in the demilitarized Golan Heights zone between Syria and Israel has gone missing, the United Nations said on Monday."We can confirm that a staff member is not accounted for and we are in touch with the relevant parties to determine what has happened," UN spokesman Farhan Haq said. "We have no further comment at this time."The UN force in the Golan Heights, which Israel captured from Syria in a 1967 war, is called UNDOF. Syrian troops are not allowed in the area of separation under a 1973 ceasefire formalized in 1974.Israel and Syria are still technically at war. The United Nations has warned that the two-year-old Syrian civil war which has killed nearly 70,000 people could spill over into the tense Golan Heights area.