The UN on Thursday highlighted “deteriorating security conditions” at a detention camp for former ISIS members in north-east Syria, which has reported a dozen murders so far this year.
UN spokesman Stephane Dujarric said 12 Syrian and Iraqi residents of Al Hol were murdered between January 1 and 16, including a female Iraqi refugee.
Another resident was critically injured in an attack.
“These disturbing events indicate an increasingly untenable security environment at Al Hol,” Mr Dujarric said in New York.
“They also jeopardise the UN and the UN's humanitarian partners' ability to safely deliver critical humanitarian assistance to its residents.”
Kurdish media outlets attributed the surge in violence at Al Hol to ISIS sleeper cells.
Al Hol is home to about 62,000 people, including 24,000 Syrians who were captured or displaced by fighting to expel ISIS from its last scrap of territory in 2019, the UN’s aid agency said.
Iraqis make up most of the foreigners in Al Hol, which also holds relatives of ISIS members from about 50 countries, including western nations.
Rights groups have long pressed European governments to let children leave the crowded camp and live with family members.
Officials in Britain, France, Germany and other countries with citizens in Al Hol fear the lock-up is a breeding ground for extremism and worry about releasing thousands of inmates with radical views.
UN aid chief Mark Lowcock on Wednesday told the Security Council that most detainees at Al Hol were children under 12, who were “growing up in unacceptable conditions” during a “surge in violent incidents”.
“The responsibility for security inside the camp rests with local authorities,” Mr Lowcock said.
“Security must be provided in a manner that does not endanger residents or violate their rights, and that does not restrict humanitarian access.”
Also on Thursday, the UN formed a three-person panel to examine how to better protect hospitals and humanitarian aid deliveries in north-west Syria from being hit by warring groups.
The panel will be chaired by Jan Egeland, a diplomat and head of the Norwegian Refugee Council, who will report back to UN Secretary General Antonio Guterres by May 10.