Beirut (AFP) - A Syrian activist who produced documentaries hostile to the Islamic State group was assassinated in Turkey Sunday, according to the group with which he worked, "Raqa is Being Slaughtered Silently".

"Film maker Naji Jerf, father of two children, was assassinated... today in Gaziantep", on the border with Syria, with a silencer-equipped pistol, the group said in a statement on Twitter.

RBSS is a group of citizen journalists who work to expose human rights abuses in Raqa, the northeastern city that IS uses as its de facto capital in Syria.

A friend of Jerf's said he had been "supposed to arrive in Paris this week after receiving, along with his family, a visa for asylum in France".

Jerf was also editor in chief of Hentah, a Syrian magazine that reports on the "daily lives of Syrian citizens", said the publication's website.

Turkish media reported that the 37-year-old had been producing a documentary on massacres carried out by IS jihadists when he was killed.

"He was hit by a bullet in the head as he was walking in the street and taken to hospital, where he died," the T24 news website reported.

This is not the first time a Syrian occupation figure has been murdered in Turkey.

At the end of October, IS claimed responsibility for killing militant Ibrahim Abdelkader and a friend. They were found decapitated in a house in Sanliurfa in southern Turkey.