Opprørsstyrker, deriblant den al-Qaida-tilknyttede al-Nusra-fronten, har erobret et viktig oljefelt fra Assads styrker.   Videos posted online showed scores of black-clad rebels walking though a large arch over an entrance to the Omar oil field, rummaging through its buildings and standing atop tanks. The Syrian Observatory for Human Rights said a number of rebel brigades […]