Syrian rebels are locked in a bitter and violent struggle—with each other. Hostilities between Syria's more moderate rebel factions and the al-Qaeda-affiliated Islamic State of Iraq and Syria exploded into open warfare on Friday, and it's been so costly that the head of another al-Qaeda affiliate, the al-Nusra Front, is calling for an Islamic court to be set up to settle disagreements, the New York Times reports. Abu Mohammed al-Jolani said the fighting was the result of the "incorrect policies" of the ISIS, but that if there wasn't a ceasefire soon, "the whole battlefield … will pay the price of losing a great jihad."
Other rebels accuse the ISIS—which wants to combine Iraq and Syria into one Sunni-ruled country—of hogging resources, applying strict social codes, and kidnapping and killing its foes. So far at least 300 people have died in the rebel in-fighting since Friday, including dozens of civilians, according to the Syrian Observatory for Human Rights, and rebels today captured a hospital-turned-ISIS base in Aleppo, the AP reports. The infighting also highlights a challenge for Saudi Arabia, which is backing the rebels in hopes of ousting Assad's Shiite, Iran-affiliated regime, but is uneasy about the potential for jihadist spill-over, the Times adds.