BEIRUT (Reuters) - The main supply route into government-held areas of Aleppo has been cut by fierce fighting between Syrian government forces and Islamic State, a group that monitors the civil war said on Saturday.
Islamic State fighters launched an attack on a road southeast of the northern city on Friday morning, initially detonating two car bombs, according to the British-based Syrian Observatory for Human Rights.
The Observatory, which reports on the Syrian war using a network of sources on the ground, said several dozen combatants from both sides had been killed.
Islamic State members, speaking to Reuters via internet from inside Syria, said their group had taken control of the road southeast of Aleppo -- Syria's most populous city and commercial hub before the war broke out in 2011.
There was no mention of the battle on Syrian state media, which reported that government forces had seized control of the village of al-Jaboul in a nearby area. Syrian officials could not immediately reached for comment.
Aleppo is divided into a western section controlled by the government, and an eastern section held by insurgents.
The attack by Islamic State on the road appears to be a response to the government advance towards the Kweiras air base, where Syrian troops are besieged by Islamic State fighters.
The government ground offensive is backed by allied militia and Russian air strikes.
A separate ground offensive is also targeting Syrian rebel groups to the south and southwest of Aleppo and government forces have captured a number of villages in that area.