BEIRUT (Reuters) - The United Nations said on Tuesday it was worried about 8,000 Syrians trapped by fighting north of Aleppo where Islamic State has advanced against rebels, and that both Kurdish and rebel authorities had hindered people fleeing the area.
The fighting has displaced thousands more Syrians near the Turkish frontier where more than 160,000 people are already sheltering, most of whom fled fighting earlier this year, the U.N. says.
"An unknown number of people are also unable to flee due to fighting and the closure of the main road leading north towards the town of Azaz in northwestern Syria," said a joint statement from the Resident and Humanitarian Coordinator for Syria and the Humanitarian Coordinator for the Syria Crisis.
Islamic State advanced in recent days into the opposition-held town of Marea.
The Turkish-backed rebels who are battling Islamic State north of Aleppo have also been involved in hostilities with the Syrian Kurdish YPG militia, which controls wide areas of territory to the west of Marea.
In a separate report on the situation, the U.N. Office for the Coordination of Humanitarian Affairs (OCHA) said civilians fleeing the IS advance had been prevented by Syrian Kurdish authorities from entering areas under their control in response to rebel shelling of a Kurdish-held area of Aleppo.
It said about 2,000 people had managed to evacuate Marea and nearby Sheikh Issa, which were encircled by Islamic State on May 27. "However, an estimated 7,000 civilians still remain inside and unable to leave due to restrictions imposed by Kurdish authorities," it added. OCHA said this was a Kurdish response to rebel shelling of Aleppo's Kurdish-held Sheikh Maqsoud area.
Meanwhile, opposition authorities in the rebel-held town of Azaz near the Turkish border had issued a directive on May 24 to not let in any more people fleeing Islamic State-held areas, OCHA said.
The court that issued the order cited fears of infiltration by covert Islamic State militants posing as internally displaced people (IDPs), after 8,000 IDPs arrived in Azaz.
"Humanitarian agencies have continued to suspend operations and evacuate staff from towns in close proximity to hostilities," the OCHA report said.
Writing by Tom Perry; Editing by Angus MacSwan and Raissa Kasolowsky