Two Syrian anti-Daesh activists have been found beheaded in a house in southern Turkey.

The bodies of 20-year-old activist Ibrahim Abdulqader and Fares Hamadi, also in his 20s, were found in Hamadi’s apartment in the city of Sanliurfa, nearly 60 kilometers from the Turkish border with Syria, Al-Jazeera reported Friday, citing an anti-Daesh activist group called “Raqqa is Being Slaughtered Silently (RBSS).”

Raqqa is a northeastern Syrian province and also a city heavily controlled by the foreign-backed Daesh terrorist group.

The RBSS said the incident in Turkey was the first such attack on its members in Turkish territory, where Daesh reportedly maintains presence.

Several members of the activist group had been murdered inside Syria and around Raqqa in the past; but the Friday killings were the first against RBSS members outside the country.

A Raqqa native, Abdulqader fled his hometown to Turkey while studying for his high school diploma in late 2013, after he was arrested and tortured by Daesh forces.

Having been formed in April 2014, shortly after the Takfiri terror group began to consolidate control over Raqqa, the RBSS runs a network of secret correspondents that operate in and around the city and provide accounts of Daesh atrocities in the area.

Since the foreign-backed crisis erupted in Syria in March 2011, an assortment of armed terrorist groups, including Daesh, have been fighting in the country to topple the government in Damascus.

Turkey has time and again been accused of being one of the main supporters of the militant groups operating in Syria, with reports saying that Ankara actively trains and arms the Takfiri militants there and facilitates their safe passage into the Arab country.