Human Rights Watch said it was investigating the same rebel group that claims it has captured UN peacekeepers for executing captured Syrian soldiers earlier this week.
Peter Bouckaert of the human rights monitoring group said it was investigating the involvement of the "Martyrs of Yarmouk" brigade in a video showing the execution of detained Syrian soldiers posted on the Internet yesterday.
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The hospital was last attacked just three days ago, something that UN Secretary General Ban Ki Moon denounced as a war crime.
Former UKIP leader Nigel Farage has flown to the US to help coach presidential candidate Donald Trump ahead of his next debate.