Many civilians and Kurdish-led fighters are reported to have been killed or wounded in clashes with Islamic State militants in north-eastern Syria.
The militants targeted displaced people near Shaddadi, in Hassakeh province, the Syrian Observatory for Human Rights and pro-government al-Mayadeen TV say.
They put the death toll at more than 25, but Syria's official Sana news agency reported only one death.
The US-backed Syrian Democratic Forces alliance is battling IS in the area.
The force controls large parts of Hassakeh province and will soon launch an offensive to retake the de facto IS capital of Raqqa, 150km (95 miles) to the west.