beirut rebel group northern syria hand control major border cross turkey-backed syrian opposition government tuesday senior rebel official say hand bab salama cross turkish border jabha shamiya rebel group aim strengthen opposition government help put end factional rivalries head political office khaled aba say urge rebel follow jabha shamiya example hand cross turkish border interim government solution liberate areas put end terrorism put end factionalism state division liberate areas say aba member opposition delegation geneva peace talk bab salama cross main gateway opposition-held area north neighbor turkey carve de facto buff zone military incursion target islamic state kurdish group last year efforts underway area merge organize plethora rebel group whose rivalries lead factional fight weaken syrian opposition throughout conflict jabha shamiya major force aleppo syrian government ally defeat opposition last year join national army operate authority interim government defense ministry aba say also hand control train camp defense ministry say opposition government base town azaz short distance turkish border launch last year turkey euphrates shield operation drive islamic state swathe territory include cities al-bab jarablus prevent territorial gain kurdish group deem threat ankara syrian rebel hand border cross opposition government