英国首相誓言将击败伊斯兰国

British Prime Minister David Cameron has vowed to defeat the threat posed by Islamic State militants following the beheading of a British aid worker by the group.

Mr. Cameron spoke in London Sunday, one day after the group released a video showing the killing of David Haines.

He said the 44-year-old father of two was murdered in the most callous way imaginable by Islamic State, a group Mr. Cameron described as the "embodiment of evil."  The prime minister vowed to hunt down and bring to justice those who killed Haines.

Mr. Cameron said Islamic State is a fanatical organization that is planning attacks across Europe. He said it claims to act in the name of Islam, but he stressed that Islamic State militants "are not Muslims, they are monsters."

Mr. Cameron said Britain must confront the menace of Islamic State and will do so by working with the Iraqi and Kurdish regional government, continuing to provide humanitarian aid to those who have fled the group, and continuing to support U.S. military actions against Islamic State militants.

In the execution video released by Islamic State, Haines' hooded executioner blames the British prime minister for joining forces with the United States against the group.  The executioner warned that the decision will drag the British people into "another bloody and unwinnable war."