Islamic State video should be treated as propaganda

An Islamic State video showing a young boy and an older masked militant speaking with British accents is a propaganda tool that serves as a reminder of the barbarity of the group, a spokeswoman for Prime Minister David Cameron said on Monday.

The video, which has not been independently verified, shows the killing of five men accused of spying for the West while the masked man warns that Islamic State will one day occupy Britain.

"It serves as a reminder of the barbarity of Daesh and what the world faces with these terrorists. It is also clearly a propaganda tool and should be treated as such," the spokeswoman said, referring to Islamic State by one of its Arabic acronyms.