The Associated Press reports: Kurdish militias battled al-Qaida-linked rebel groups in northeastern Syria on Tuesday in the latest round of heavy fighting that has helped fuel a mass exodus of civilians from the region into neighboring Iraq, activists said.

Clashes between Kurdish fighters and Islamic extremist rebel groups have sharply escalated in Syria’s northern provinces in recent months. The violence, which has left hundreds dead, holds the potential to explode into a full-blown side conflict within Syria’s broader civil war.

Tuesday’s fighting, which pitted Kurdish militiamen against rebels from the Islamic State of Iraq and the Levant, was focused in three villages near the town of Ras al-Ayn in the predominantly Kurdish Hassakeh province, according to the Britain-based Syrian Observatory for Human Rights monitoring group. There was no immediate word on casualties.