A video showing what appears to be rebels executing Syrian soldiers most probably reveals war crimes and could be used as evidence to bring the perpetrators to justice, the UN human rights body said Friday. \"At this point, on day one, all what (we) can say (is) it\'s a very shocking piece of video,\" Rupert Colville, spokesman for UN High Commissioner for Human Rights Navi Pillay, said in Geneva. \"If it is as it appears at this point, then it would be a war crime,\" he added. \"It is very likely that this was a war crime, another one.\" He was reacting to a video posted on YouTube of what appeared to be Syrian rebels beating around 10 injured soldiers before lining them up on the ground and executing them with automatic rifles. The Syrian Observatory for Human Rights said Thursday that rebels had killed 28 soldiers during attacks on three army checkpoints. Colville said he and his colleagues had only just seen the video and that it was difficult to verify who was involved. \"Like other videos of this sort, it is difficult to verify immediately.... It will be examined carefully,\" he said. At first glance, he said, it appeared that \"these were soldiers who were no longer combatants and therefore, at this point, it looks very (much) like a war crime.\" In July 2012, the International Committee of the Red Cross (ICRC) defined the Syrian conflict as a civil war, meaning the Geneva convention on the treatment of victims of war applies. This means that executing a soldier not in combat, with no means to protect himself, is considered a war crime. \"Once again, we call on all parties to the conflict in Syria to respect international human rights law,\" Colville said, lamenting that the video appeared to be \"the latest in a string of documented summary executions by opposition factions as well as by government forces and groups affiliated with them, such as the Shabbiha.\" He stressed though that the perpetrators of such atrocities should be under no illusion they could get away with their crimes. \"Accountability will follow,\" he said, adding that the video could well be used as evidence in legal proceedings. The UN Human Rights Council created a commission just over a year ago to investigate serious human rights abuses in Syria, but it has yet to actually gain access to the country. The commission, which recently added former war crimes prosecutor Carla del Ponte to its ranks, has however conducted more than 1,000 interviews with perpetrators and victims in the conflict, and reported in August that war crimes appeared to have been committed by both the regime and, to a lesser extent, rebel forces. More than 36,000 people have died in the 19-month conflict, according to the Syrian Observatory for Human Rights.