British Prime Minister David Cameron said on Sunday that the UK will "hunt down" the killers of David Haines, a British aid worker, after a video of the 44-year-old's beheading was released by Islamic State (IS) militants on Saturday night.
UK will work with allies to defeat the terrorist group IS, and that countries must "drain this poison from our society," he said.
"We must confront this menace. We must drive back, dismantle and destroy [IS]," Cameron said in his remarks. He reiterated that Islam is a religion of peace, and said of the militants, "they are not Muslims; they are monsters."
The 44-year-old Haines was abducted in Syria in 2013 while working for an international aid agency.