Opposition activists have posted a video purporting to show at least 51 muddied male bodies alongside a river bank in the rebel-held Bustan al-Qasr neighbourhood of Aleppo.
The video, which is too graphic to post, follows a man walking along a river bank past dozens of male bodies with their hands tied and blood coming from their heads.
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The prime minister has said the debate over Britain's EU membership has affected his long-term friendship with the mayor of London.
Tonight a band of cloud and rain will spread into Scotland and Northern Ireland.
Greenpeace has obtained leaked documents which reveal how much the US has been pushing the EU on the TTIP trade agreement.