Militants of the Islamic State terrorist group beheaded three men it accused of treason in Syria's eastern province of Deir Ezzor, a monitoring group said on Wednesday.
One of the men was a former IS fighter and the other two were purportedly collaborating with anti-IS movements in neighbouring Turkey, the Britain-based Syrian Human Rights Observatory reported.
The trio was beheaded in the eastern town of al-Shil after being arrested by IS militants when they crossed back into Syria from Turkey, the watchdog said.
IS wrested the area around al-Shil from the Al-Qaeda affiliated Nusra Front on May 15.
IS already controls most of Deir Ezzor province and around half of its provincial capital, Deir Ezzor, where it launched an offensive in May.