UK Prime Minister David Cameron has condemned a "disgusting and despicable" video apparently showing a second US journalist being beheaded by Islamic State militants.
The Prime Minister said: "It is an absolutely disgusting and despicable act.
"I will be making a statement later."
The footage seemingly shows the same masked jihadi, believed to be British, who murdered James Foley last month.
The victim, named as American Steven Sotloff, is again pictured in an orange jump suit before the brutal act.
Mr Sotloff, who freelanced for Time and Foreign Policy magazines, was seized in Syria in August 2013 and had not been seen until he appeared in a video released online last month by the IS group.