The New York Times said it has obtained a video of Syrian rebels executing soldiers, fresh evidence of opposition brutality that comes at a crucial moment as world leaders debate launching strikes on the Damascus regime.
The footage is the latest indication that some in the Syrian opposition, which Washington backs, are behaving as ruthlessly as the regime they are fighting to oust.
It is also a reminder of how violent and criminal Syria has become as the US Congress prepares to vote on attacking President Bashar al-Assad's regime for its alleged use of chemical weapons.
The newspaper said the video was smuggled out of Syria by a former rebel upset by the killings.
The footage, which the newspaper said was shot in 2012 and sneaked out of the country a few days ago, shows seven Syrian soldiers, some with welts on their backs and their faces pressed in the dirt.
A military commander recites a revolutionary verse.
"For fifty years, they are companions to corruption," he said. "We swear to the Lord of the Throne, that this is our oath: We will take revenge."
Once the poem is over, the commander shoots the first prisoner in the back of the head and fellow gunmen quickly follow suit.
A key concern for the United States as it weighs an intervention is who among the multifaceted Syrian opposition it can trust as allies to replace Assad.
The Senate Foreign Relations Committee this week passed a resolution allowing the use of force against Syria over an August chemical weapons attack, albeit with restrictions, and more votes in the rest of the legislature are likely next week.
© AFP 2014