An al Qaeda splinter group in Syria executed at least 13 people including relatives of fighters from rival rebel groups before withdrawing from a town near Aleppo, the Syrian Observatory for Human Rights said on Friday.
The London-based monitoring group said the men killed by the Islamic State of Iraq and the Levant militants included rebels who were detained by ISIL after laying down their arms. The Observatory said their bodies had been thrown into a well, Reuters reported.
It did not say when the incident took place in Haritan, just northwest of Aleppo, one of the most contested areas in an almost three-year-old civil war between insurgents and the forces of Syrian President Bashar al-Assad.
Several Islamist and more secular rebel factions joined forces in January for an offensive to try to push their former ISIL allies out of rebel-held regions in northern and eastern Syria.
ISIL, which has attracted many foreign militants into its ranks, is a small but powerful fighting force in Syria and also operates in neighboring Iraq. It has alienated many civilians and opposition activists by imposing harsh rulings against dissent, even beheading its opponents, in areas it controls.