Prime Minister David Cameron said Wednesday it seemed "increasingly likely" that a British jihadist executed the US journalist James Foley.
Cameron, who broke off his holidays to return to London for meetings on the threat posed by Islamic State militants operating in Iraq and Syria, said "far too many" Britons had travelled to the region to take part in extremism.
He condemned Foley's killing as "brutal and barbaric" and "murder without any justification".
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