- The attack occurred in rebel-controlled Idlib province amid recent spikes in violence
- The unidentified attackers stole vehicles and equipment, activists said
The attackers also stole two vans, helmets and walkie-talkies, according to a statement from the group, which is formally known as the Syrian Civil Defense.
The Aleppo Media Center activist group also said seven volunteers were killed in an attack -- and posted video and photos of their funeral.
A procession of mostly men carried the dead to be buried, the images show. Many of the mourners wore the White Helmets badge and broke down in tears.
The Syrian Civil Defense called for northern Syrian checkpoints to detain any vehicles bearing the White Helmets logo that were not verified.
Attacked amid spikes in violence
The attack occurred in the city of Sarmin in Idlib province, which last month came mostly under the control of Hayat Tahrir Al-Sham, a coalition of Salafi jihadist groups that includes Fateh al-Sham. The latter group had been known as Jabhat al-Nusra before renouncing its ties to al Qaeda.
Idlib, one of the last Syrian provinces still beyond regime control, has been experiencing spikes in violence.
After the Syrian government -- with the help of Russian air power -- regained control of the key city of Aleppo last year, masses of opposition rebels were bussed to Idlib as part of a people-swap agreement.
The White Helmets have brought to light the scale of the Syrian conflict in a painfully visceral way, documenting their recovery operations through video and photo.