Fighting between rival US-backed groups in Syria could undermine war against the Islamic State group

BEIRUT: The weeklong clashes between rival US-backed militias in eastern Syria, where hundreds of American troops are deployed, point to dangerous seams in the coalition that has kept a lid on the defeated Islamic State group for years. That could be an opportunity for the radical group to reemerge.
The violence also points to rising tensions between Kurds who dominate the region and the mainly Arab population, opening the door for Syrian President Bashar Assad and his allies, Russia and…