DAVID CAMERON, UK PRIME MINISTER: The fact that an aid worker was taken, held and brutally murdered at the hands of ISIL [ISIS] sums up what this organization stands for. They boast of their brutality; they claim to do this in the name of Islam. That is nonsense. Islam is a religion of peace. They are not Muslims, they are monsters…

We cannot just walk on by if we are to keep this country safe; we have to confront this menace. Step by step, we must drive back, dismantle and ultimately destroy ISIL [ISIS] and what it stands for. We will do so in a calm and deliberate way, but with an iron determination. We will not do so on our own, but by working closely with our allies, not just the United States and in Europe, but also in the region because this organization poses a massive threat to the entire Middle East.