United Nations peacekeepers began withdrawing their forces on the Syrian side of the Golan Heights, CNN reported on Monday.A UN source told the network that the troops, who were seen crossing into the Israeli-controlled portion of the plateau, were being pulled out for their safety.Syria's three-year civil war reached the frontier with Israel last month when Islamist fighters overran a crossing point in the line that has separated Israelis from Syrians in the Golan Heights since the 1973 Yom Kippur War.