(UNKNOWN): Nine out of 10 civilian casualties are caused by the Taliban.
BOETTCHER: At a district center in eastern Afghanistan, not everyone is convinced by that argument. During a visit by the 101st Airborne's deputy commander in Afghanistan, Steve Townsend (ph), a village elder asserted that the Americans were killing more Afghans than the Soviets did a quarter century ago. Townsend pushed back hard.
(UNKNOWN): Look in my eyes right now. You know I'm telling the truth.
BOETTCHER: But as the words fly, so do bombs and bullets. Combat Outpost Firra (ph), situated on the Pakistan border, is often attacked. During one assault, 18 insurgents died, but soldiers know this: You can't kill your way out of Afghanistan.
(UNKNOWN): They can reconstitute faster than we can. We're so close to Pakistan that they just come right across the border.
BOETTCHER: So rather than enemy body counts, real success here is measured in how quickly Afghan feet can fill American-made boots. If the war is to end, Afghan soldiers will have to end it.
(UNKNOWN): We have to make a difference. Coming here and -- and just running around and killing the enemy and then leaving and looking back and saying, "I didn't make a difference, I didn't make a change," will cause us to never leave.
BOETTCHER: Steve Lutsky's son is the same age as young Sadekela (ph), 10. The colonel wants only one thing to come from his service here: confidence that his own son someday will not be fighting his father's war.
For "This Week," Mike Boettcher, ABC News, Forward Operating Base Clark, Afghanistan.
(END VIDEO CLIP)
AMANPOUR: And joining me now is the chairman of the Joint Chiefs of Staff, Admiral Mike Mullen.
Welcome to "This Week."
MULLEN: Good morning.
AMANPOUR: And we will discuss, of course, Afghanistan, but let me get to the breaking news this morning, the report by the New York Times of the discovery of a new nuclear facility in North Korea. How much of a threat is that to the United States, to the world?
MULLEN: Well, this validates a long-standing concern that we've had with respect to North Korea and -- and its enrichment of uranium. It also continues to validate a country that is led by a dictator who is constantly -- who constantly desires to destabilize the region. And he's done that again, certainly, with this capability, as well.
And certainly the development of nuclear weapons is a huge concern for all of us, those in the region, as well as those around the globe.
AMANPOUR: How could this have happened in secret, despite the sanctions that were put on? Practically as the sanctions were put on, this was being built.
MULLEN: Well, he's defied sanctions. There are two, actually, U.N. Security Council sanctions that he's defied in this. He's defied what he said he'd do in 2005, because he said he clearly would comply and not -- not do the -- generate this kind of capability, and yet he does.
AMANPOUR: Right. But what options, then, do you have? If sanctions are the toughest measure and he's doing it, what's your answer to that?
MULLEN: Well, I think we have to continue to bring pressure on him specifically. Those in the region -- in particular the six-party talk countries, Russia, China, the United States, Japan, and South Korea, we all -- we have to continue to do that.