Terrorist Document Found

In the Middle East, a document has been found, threatening violence against British 'occupiers':

A pamphlet warning Britons to leave the Middle East or face death has come to light in a stash of illicit propaganda... It adds: “Most of you have been in this country for quite a long time. You have learned what the word ‘terrorist’ means, some of you may even have come into direct contact with them (and heartily desire not to repeat the experience). But what do you know about them?

Which 'terrorist' group penned this piece? Hamas? Hezbollah? Or somebody else?