Money can be a very important form of "ammunition," although we should never forget that when you're being shot at the most important ammunition is real ammunition.

The Islamic State fighters in Mosul are dead men walking and I think they increasingly know it.

The task [in Afghanistan] is to reduce civilian casualties while still not hesitating to respond to enemies who are trying to kill our soldiers.

I just don't know whether it was all destroyed years ago - I mean, there's no question that there were chemical weapons years ago - whether they were destroyed right before the war, (or) whether they're still hidden.

There has, indeed, been very substantial progress in Iraq over the past year - violence is down by 80 percent, civilian deaths by about the same, and so on.

President Obama has said that our aspirations should be realistic. We are not going to turn one of the poorest countries in the world, that was plunged into 30 years of war, into an advanced, industrialized, Western-style democracy. What we want to achieve is Afghanistan's capacity to secure and govern itself.

Don't forget Yemen, where there are also extremist elements, as we saw recently.