IS kills 20 US-backed fighters in Syria: monitor

At least 20 fighters from a US-backed force fighting the Islamic State group were killed Friday in an IS ambush in eastern Syria, a war monitor said.

"The fighters were advancing during a sandstorm, they were surrounded, IS members used explosives and opened fire," said the Britain-based Syrian Observatory for Human Rights.

The Kurdish-led Syrian Democratic Forces is waging an offensive around the town of Hajin in the province of Deir Ezzor, IS's last stronghold in the country's east.