BEIRUT, Nov 28 (Reuters) - Al Qaeda-linked militants have executed the commander of a rival rebel faction and six of his men, an amateur video of the public execution showed, part of their campaign to marginalise other groups.
The Islamic State in Iraq and the Levant, or ISIL, fighting to overthrow President Bashar al-Assad, have taken advantage of a power vacuum in rebel-held areas to assert its authority over more moderate elements of the armed opposition.
The video, posted online by the anti-Assad Syrian Observatory for Human Rights monitoring group on Wednesday, shows armed men in black standing below an ISIL banner.
The Observatory said the video was taken in the northern Syrian town of Atarib in Idlib province. Its authenticity could not be independently confirmed.
A masked man on the video identifies seven men kneeling as members of the Ghurabaa al-Sham brigade, a moderate Islamist group that was one of the first to fight Assad. A man who appeared to be Commander Hassan Jazera was among them.
"Hassan Jazera is the most corrupt and the biggest thief," said the man. He spoke into a microphone to a crowd of men, some of whom used their mobile phones to film the killing.
The man, reading from a piece of paper, said Jazera's men were also charged with kidnapping and had been tried in a religious court run by ISIL. They were then shot in the head.
In May, an alliance of Islamist groups moved against Ghurabaa al-Sham following a disagreement over territory and complaints of looting. Jazera's unit of around 100 fighters was all that was left of Ghurabaa al-Sham's roughly 2,000 men, fighters from that group told Reuters this summer.
Jazera and his men were arrested by ISIL a month ago, the UK-based Observatory said.
The rise of al Qaeda in Syria has forced some in the West to temper calls for Assad's removal from power.
In August, ISIL took control of the northern border town of Azaz, expelling western-backed Free Syrian Army units. On Friday, ISIL captured a second border town, ousting a moderate Islamist rebel unit and detaining its leader.
The Syrian uprising against four decades of Assad family rule started in 2011 and erupted into a civil war after Assad's forces shot demonstrators and deployed tanks to crush the protest movement. More than 100,000 people have been killed and millions have been displaced. (Reporting by Oliver Holmes and Reuters TV, editing by Elizabeth Piper)