Heavy fighting between the Syrian army and Islamist rebels erupted on Monday on the Golan Heights, where the militants have wrested control of a key frontier crossing which had been operated by the United Nations. It was not clear whether the forces loyal to Syrian President Bashar al-Assad had managed to retake control of the Quneitra crossing from the rebels of the al Qaeda-linked Nusra Front. Persistent gunshots and explosions from mortar shells and other munitions could be heard on the Israeli-controlled side of the frontier and combatants could be clearly seen targeting each other with their weapons. At least one tank belonging to the Syrian army was also involved and some rebels could be seen a few meters (yards) away from the frontier fence. A large Syrian flag that had been flying for days between the Quneitra crossing and the abandoned town […]