Updated Saturday, November 3, 2012 at 12:16 AM
GENEVA — The United Nations said Friday that a new video from Syria circulating on the Internet that appears to show anti-government fighters kicking and summarily executing a group of frightened soldiers or militiamen could, if verified, represent evidence of a war crime to prosecute the perpetrators.
The video, which appeared Thursday, generated widespread attention internationally and provoked debate among insurgents and their sympathizers inside Syria. The video also illustrated what rights activists called a distressing trend of atrocities committed by both sides in the conflict.
"It looks very likely that this is a war crime, another one," Rupert Colville, a spokesman for the U.N. high commissioner for human rights, said in Geneva, at its headquarters.
U.N. investigators had collected evidence of war crimes and crimes against humanity by government and rebel forces that could support prosecutions of those responsible by national or international tribunals, Colville said. The new video, assuming its authenticity were proved, could be part of that evidence, he added.
"The people committing these crimes should be under no illusion that they will escape accountability," Colville said.
Thousands of videos depicting violence and combat in Syria have been posted on the Internet since the conflict began, mostly by anti-government activists aiming to vilify the behavior of the Syrian military and pro-government militia known as the shabiha.
Many videos cannot be independently corroborated, and experts are cautious about drawing conclusions from footage that could have been digitally fabricated or altered.
But the videos are often one of the few ways to obtain information and assess the conflict in a country where outside media coverage is restricted and dangerous.
Accounts of suspected rebel atrocities and the use of car bombs and other explosives in civilian areas, along with the arrival in Syria of Islamist militants from other nations, have tarnished the "freedom-fighter" image that opposition representatives have sought to project. The reports have complicated opposition efforts to garner more aid from the West and elsewhere.
This week Secretary of State Hillary Rodham Clinton urged the leadership of the Syrian opposition to be "on record strongly resisting the efforts by extremists to hijack the Syrian revolution."
The video purporting to show the extrajudicial killings of loyalist soldiers appeared to have been made at the Hamcho military checkpoint in Saraqeb, a town in Idlib province in northern Syria that has been the scene of particularly brutal fighting.
In the video, captors force 10 prisoners, some pleading for their lives, to lie next to or atop one another. The anti-government fighters, whose precise identities or affiliations were not clear, yell "Allah Akhbar!" or "God is great!" A few parade before the camera as others kick and herd the prisoners into a pile before shooting them from multiple directions.
Ann Harrison, deputy director of Amnesty International's Middle East and North Africa program, said the video demonstrated an "utter disregard for international humanitarian law by the armed group in question."
The killers apparently did not know, or did not care, about an important legal change in the definition of the Syrian conflict decreed in July by the International Committee of the Red Cross. It said Syria was engrossed in a civil war, subject to the Geneva convention on the treatment of victims of war. Under that change, the execution of a soldier not in combat and with no means of protection is considered a war crime.
The video from Saraqeb provoked protest within Syria, with some activists saying the killings did not represent the values that inspired their revolution against four decades of repression by the family of President Bashar Assad.
"We don't want those who are liberating us from killers to resemble them and take on their values," Iyas Kadouni, an activist in Saraqeb, wrote on his Facebook page.
Some rebel military commanders said such incidents were inevitable. "I cannot stop these angry fighters," said one commander in Saraqeb reached by Skype. "How can I control a fighter who lost a brother or father in front of his own eyes?"
Material from the Los Angeles Times is included in this report.
In amateur video taken Thursday, an alleged rebel gunman steps on a captured soldier lying on the ground in Saraqeb, northern Syria. Later in the video, the rebels appear to kill the group of captured soldiers, spraying them with bullets as they lie on the ground.