At least 31 killings have rocked a camp holding Daesh terror group relatives in Syria since early January, a Kurdish official said on Wednesday, with aid groups warning of a "nightmare”.

It was the latest evidence of deteriorating security at Al Hol camp in the Kurdish-run northeast, where Medecins Sans Frontieres (MSF) had to temporarily suspend operations this week after the killing of one of its team members.

"Since the start of 2021, 31 people have been killed — six of whom were murdered with a sharp object, while the rest where shot dead,” said camp official Jaber Sheikh Mustafa.

The toll has more than doubled since February 8 when it stood at 14, according to Kurdish authorities.

"We believe that Daesh sleeper cells are behind these murders” that especially target Iraqi residents of the camp, Mustafa told AFP.

But a humanitarian source said recently that tribal score-settling between residents could also be to blame for some murders.

Al Hol holds almost 62,000 people, mostly women and children, including Syrians, Iraqis and thousands from Europe and Asia accused of family ties with Daesh fighters.

Most camp inhabitants are Syrians or Iraqis displaced by the Kurdish-led battle against Daesh that took back the group’s last scrap of territory in March 2019.

MSF said on Tuesday that it was suspending its operations in the camp after one of its local team members was shot dead in his tent on February 24.

"People are being killed with a brutal frequency, often in the tents where they live,” said MSF’s emergency manager, Will Turner.

"This is not a safe environment and certainly not a suitable place for children to grow up in. This nightmare must stop.”

Despite chronic overcrowding at Al Hol, the number of camp guards was reduced from 1,500 in mid-2019 to 400 in late 2020, the UN said in a February report.

Some detainees see the camp as the last vestige of the cross-border "caliphate” Daesh declared in Syria and neighbouring Iraq in 2014, it said.

Apart from murders, a camp blaze on Saturday killed six people, including five children, the Kurdish administration said.

At least 36 others were injured in the fire, officials told a press conference on Wednesday.

Following the deaths, UN children’s agency UNICEF called for the "safe reintegration and repatriation of all children” in Al Hol.

The UN humanitarian agency OCHA warned that that "no one — most of all innocent children — should be living under the challenging and potentially dangerous humanitarian conditions” in the camp.