The so-called Syrian Observatory for Human Rights said on Sunday that a parliamentary source in Damascus, on condition of anonymity, confirmed that Mujhem al-Sahu from Deir ez-Zor province in eastern Syria had been executed.

A video released by the militants after kidnapping Sahu showed armed men standing in front of a flag of Saudi-backed Liwa al-Nasr militant group.

However a report by the Syrian D Press news website said militants from al-Qaeda's Islamic State of Iraq and Levant have announced responsibility for the killing.

Last month Syrian lawmaker, Mohanna Faisal al-Fayyad had been kidnapped by extremist militants.

The monitoring group said Ahrar al-Sham militants and extremists from the al-Qaeda-affiliated Islamic State of Iraq and the Levant (ISIL) abducted Fayyad on October 27.

He was kidnapped after two days of clashes between members of his tribe and militant groups.

The war in Syria started in March 2011, when pro-reform protests turned into a massive insurgency following the intervention of Western and regional states.

Since the start of the war al-Qaeda affiliated groups have been emerging under different names in Syria, fighting at the side of the US-backed opposition which is leading one of the bloodiest conflicts in the recent history.

According to the United Nations, more than 100,000 people have been killed and millions displaced due to the turmoil that has gripped Syria for over two years.

SHI/SHI