Beirut: An Islamic State attack in an area held by the US-backed Syrian Democratic Forces (SDF) in northeast Syria killed at least 38 people on Tuesday including 23 civilians, the Syrian Observatory for Human Rights said.

The attack on Rajm al-Salibi, the location of a checkpoint and refugee camp near the border with Iraq, led to fierce clashes, injuring dozens, the Britain-based war monitor said.

This frame grab from video provided by the Hawar News Agency, shows people wounded in an attack by the Islamic State group receiving treatment at a clinic in Hasakeh province, Syria. Credit:via AP

The SDF battled Islamic State since dawn in nearby areas of Hasaka province, which Kurdish forces largely control, it said.

An adviser to the SDF, Nasser Haj Mansour, confirmed that several civilians died, including people escaping Islamic State in Syria's Deir al-Zor and in Iraq.