Seven members of Syria’s White Helmets rescue group have been shot dead in their base by unidentified attackers.
The killings happened in the jihadist-held northwestern town of Sarmin, six miles (9km) east of the city of Idlib.
The group, officially called Syria Civil Defence (SCD), was nominated for the Nobel Peace Prize last year for its work pulling civilian victims of bombing in Syria out of rubble.
It was active in rebel-held eastern Aleppo before the territory was seized by forces loyal to President Bashar al Assad.
The SCD receives millions of pounds worth of funding from many Western government including the UK and the US.
The White Helmets said in a statement: “The civil defence centre in Sarmin was the target of an armed attack by unknown assailants in which seven volunteers were killed.
“Two minibuses, some white helmets and walkie-talkies were stolen.”
It was not immediately clear whether the raid was carried out for political or criminal motives.
The UK-based Syrian Observatory for Human Rights said the seven volunteers who died had all been shot in the head.
The observatory’s director, Rami Abdel Rahman, said: “Colleagues came in the morning for the change of shift and found them dead.”
The White Helmets emerged in 2013, working to rescue civilians in many rebel-held areas.
They have since gained widespread international renown for their daring rescues, with footage often taken and circulated on social media.
Although its volunteers work in exclusively rebel-held areas, the group insists it is not partisan.
President Bashar al Assad’s government, meanwhile, accuses the group of faking videos and being a tool of its international donors.
Independent Western media outlets say state-linked Russian news agencies have accused the SCD of being frauds as part of a systematic information war against it.
Critics have also claimed rebel fighters, including jihadists, operate in their ranks.
Sarmin is controlled by the Hayat Tahrir al Sham jihadist alliance, which was formed when the Nusra Front merged with other groups.