The United Nations today said video appearing to show Syrian rebels killing regime forces in an execution-style line-up probably constitutes a "war crime," but cautioned that the graphic online footage has not yet been verified, reported Reuters.
However, Free Syrian Army (FSA) representative Hossam al Sarmani told CNN today the killings were the work of "extremists" unassociated with the rebel group.
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Rights groups have roundly condemned the video, which was posted online Thursday and reportedly shows the brutal killing of about a dozen Syrian government forces, said Australia's ABC News.
"Like other videos of this sort, it's difficult to verify immediately in terms of location, who's involved," Reuters cited UN human rights spokesman Rupert Colville as saying today, adding that agency will need to "examine this carefully."
"But the allegations are that these these were soldiers who were no longer combatants," Colville said. "And therefore, at this point it looks very likely that this is a war crime."
"This execution did take place, and this is the heinous truth," Sarmani told CNN, vowing to find and hold those responsible "until they can by tried by international law or the new Syrian law, God willing."
The gruesome footage adds to growing concern over the humanitarian crisis in Syria, where fighting between armed rebels and Syrian President Bashar Al-Assad's regime is believed to have taken over 30,000 lives over the past 18 months.
The BBC's Jim Muir said summary executions in Syria have become routine in conflict-ridden areas, describing them as "common practice."
The video is said to show government soldiers being mocked as "Assad's Dogs" before being shot repeatedly, according to Reuters.
Amnesty International on Thursday issued a statement of concern over the violence depicted in the video, with director Ann Harrison saying the "shocking footage depicts a potential war crime in progress, and demonstrates an utter disregard for international humanitarian law by the armed group in question."
The UK-based rights group said they have not been successful in contacting the Syrian rebel group believed responsible.
Rebels launched an attack Thursday that killed 28 soldiers near Saraqeb, a highway town, Reuters cited activist groups as saying.
But the UK-based Syrian Observatory for Human Rights said violence yesterday took the lives of over 70 regime forces, 43 civilians, and 38 rebels, reported BBC.