BEIRUT -- A video that appears to show a unit of Syrian rebels kicking terrified, captured soldiers and then executing them with machine guns raised concerns yesterday about rebel brutality at a time when the United States is making its strongest push yet to forge an opposition movement it can work with.
UN officials and human rights groups believe President Bashar Assad's regime is responsible for the bulk of suspected war crimes in Syria's 19-month-old conflict, which began as a largely peaceful uprising but has transformed into a brutal civil war.
But investigators of human rights abuses say rebel atrocities are on the rise.
At this stage "there may not be anybody with entirely clean hands," Suzanne Nossel, head of the rights group Amnesty International, told The Associated Press.
The United States has called for a major leadership shake-up of Syria's political opposition during a crucial conference next week in Qatar. Washington and its allies have been reluctant to give stronger backing to the largely Turkey-based opposition, viewing it as ineffective, fractured and out of touch with fighters trying to topple Assad.
But the new video adds to growing concerns about those fighters and could complicate Washington's efforts to decide which of the myriad opposition groups to support.
"We condemn human rights violations by any party," U.S. State Department spokeswoman Victoria Nuland said, commenting on the video. "Anyone committing atrocities should be held to account." She said the Free Syrian Army has urged its fighters to adhere to a code of conduct it established in August, reflecting international rules of war.
The summary execution of the captured soldiers, purportedly shown in an amateur video, took place Thursday during a rebel assault on the strategic northern town of Saraqeb, said the Britain-based Syrian Observatory for Human Rights, an activist group.
It was unclear which rebel faction was involved, though the al-Qaida-inspired Jabhat al-Nusra was among those fighting in the area, the Observatory said.