Heavy fighting between the Islamic State group and rebels gripped a town in northeastern Syria Saturday, a monitor and an activist said, after a lightning assault by the jihadists cut a main supply route.
"Heavy clashes took place overnight between IS fighters and rebels inside the walls of Marea town," the Syrian Observatory for Human Rights said.
IS swept through rebel-held territory early Friday in a shock offensive in Aleppo province, cutting off the main road between Marea and Azaz, 20 kilometres (12 miles) to the northeast near the Turkish border.
The surprise advance came as the jihadist group faced an offensive by a US-backed Kurdish-Arab alliance in its own heartland of Raqa province further east.
Maamoun Khateeb, a journalist and activist from Azaz, told Agence France Presse that IS attacked Marea early Saturday mainly from the east and north using tanks and two car bombs.