The United Nations human rights office says a video that appears to show Syrian rebels killing soldiers who had surrendered, appears to constitute a war crime that should be prosecuted.

The United Nations human rights office says a video that appears to show Syrian rebels killing soldiers who had surrendered, appears to constitute a war crime that should be prosecuted. The incident looks to be the latest atrocity committed by opposition fighters seeking to topple President Bashar al-Assad.

The disturbing scene was circulated on-line.

Syrian rebels appear to be executing 28 government soldiers on Thursday, after attacking three army checkpoints around Saraqeb, a town on Syria’s main north-south highway.

Video footage shows some of the dead were shot after they had surrendered.

Rebels berated them, before appearing to fire round after round into their bodies as they lay on the ground.

The UN’s human rights office said on Friday that the amateur video must be verified but it appears to constitute a war crime that should be investigated and prosecuted.

Rupert Colville, Spokesperson, UN High Commissioner of Human Rights, said, "We need to examine this carefully. It will be examined carefully, but the allegations are that these were soldiers who were no longer combatants. And therefore, at this point it looks very likely that this is a war crime, another one. There’s a lot of evidence for many of these crimes that have been taking place, this video, if it’s verified, if the details become a little clearer, could well be part of that evidence."

Reports of serious human rights abuses by elements within the armed opposition have been on the rise.

The latest footage, which has spread across the world, has dealt a further blow to the rebels’ image and is embarrassing their foreign supporters.

Washington and its allies have been hesitant to give stronger support to the rebels in part because of worries over its multiple divisions and lack of organization.