It seems that Nosra front and its allies have decided to get rid of those militias supported by USA and Kurds at the north west of Syria. Today saw clashes at new fronts there between the two parties. This comes after months of having US airfighters targeting Nosra fighters in that area without having a clear reason for these targetings. By the way, for those who don't know, Nosra is not an Ally to IS. They even fight each other in some fronts in Syria.