Forces loyal to the Syrian government are taking advantage of deepening rifts among Syria's feuding rebels to advance into rebel-held territory in the northern part of the country, overturning some long-held assumptions about the war.
The resignation Sunday of a top leader in the U.S.-backed Free Syrian Army further underscored the extent to which rebel infighting is undermining the effort not only to topple President Bashar Assad but also to hold on to territory won by the opposition in the past two years of conflict.
Col. Abdul Jabbar Akaidi, one of the chief recipients of what little American aid has been provided to the rebels, said he was standing down to protest the rebel bickering, which he blamed for the capture on Friday by Assad loyalists of the strategic town of Safira, southeast of the key city of Aleppo.