BEIRUT (Reuters) - Syrian rebels in a pocket of land near where the Syrian, Lebanese and Israeli borders meet are negotiating a deal with the government to leave for other insurgent-held areas, rebel officials there said. The Syrian army, backed by Russian air power, Shi ite militias supported by Iran and local fighters from the Druze sect have besieged the rebel enclave around Beit Jin for weeks. In recent days it captured various positions, leaving the rebels trapped inside the town itself.  There is now negotiation on the departure of fighters and those who wish to leave with them,  said Abu Kanaan, an official in a local rebel group.  The militias are trying to convince them to evacuate to Idlib... There has been no agreement reached yet,  said Ibrahim al-Jebawi, an official with a Free Syrian Army faction familiar with the situation.  Syria s army and its allies have increasingly pushed for such evacuation deals for rebel enclaves near big cities or in other strategic locations after long periods of siege and bombardment.  The area around Beit Jin is sensitive because of its location next to the Israel-controlled Golan Heights.  Israel wants to keep Lebanon s Hezbollah, the most powerful of the Iran-backed militias aiding Syrian President Bashar al-Assad against the rebel groups, far away from its border with Syria.  It has repeatedly targeted military positions in Syria near the border after stray projectiles crossed into Israeli-controlled areas, and it has struck Hezbollah convoys and weapons caches inside Syria. 