Jihadists from the Islamic State (IS) group have taken over six villages in the northern Syrian province of Aleppo, a monitoring group has said.
The Britain-based Syrian Observatory for Human Rights said the extremist group had managed to seize the villages and are not far from the border with Turkey.
The fighting is still going on over the control of another village in the area, Arshaf, the NGO said.
The take over was a strategic prize, because it would open the way for the group to attack the towns of Marea and Azaz, it said.
Marea has a stronghold of the Islamic Front, a coalition of Islamist groups that is among those fighting against IS and Azaz sits next to the border crossing with Turkey, which would be a valuable asset to IS as it seeks to expand its self -declared "caliphate" in the territory it holds in Syria and neighbouring Iraq.
The group took over the areas "after fierce clashes with rebels and Islamist battalions that remained in the area after Al-Nusra Front and other Islamist battalions withdrew at the end of July," the NGO said.
It further said that Al-Nusra Front, which is Al-Qaeda's Syrian branch, joined moderate and Islamist rebel groups in a coalition that began fighting the Islamic State in January.
But in recent weeks, Al-Nusra has also fought other rebel groups, further complicating the status of the armed opposition in Syria.
IS emerged from Al-Qaeda's one-time branch in Iraq, and initially fought alongside Syria's opposition, including moderate rebels and Al-Nusra fighters.
The group was pushed out of much of the territory it held in Aleppo province by the coalition of moderate and Islamist rebels that turned against it in January.
But it has been able to recapture some of that lost ground, and is advancing in Aleppo with the assistance by the decision of the Islamist Dawud Brigade to pledge allegiance to the Islamic State.
More than 170,000 people have been killed in Syria since the conflict began there in March 2011.
