JUDY WOODRUFF: North Korea today hailed its test of a new intermediate-range missile and claimed that it can now hit U.S. bases in the Pacific with a nuclear warhead.

State TV broadcast footage of Sunday's launch. The missile traveled nearly 500 miles, but analysts said it could have a maximum range of 2,500 miles.

So, just where is the North in its development of missile technology and its nuclear program?

For that, we turn to Jeffrey Lewis. He's the director of the East Asia Non-Proliferation Program at the Middlebury Institute of International Studies in Monterey, California.

Jeffrey Lewis, thank you very much for joining us.

This sounds like quite an advance on the part of the North Koreans. Tell us more about this missile test. What exactly was it yesterday?

JEFFREY LEWIS, Middlebury Institute of International Studies: Well, it's a brand-new type of missile.

We'd seen a version of this in a parade just a month ago, but what's really striking is, it seems to use a new engine that the North Koreans designed themselves. So, in the past, normally, they have copied engines from other places. This looks like the first engine that's fully North Korean, so it's a big step forward for them.

JUDY WOODRUFF: So, what does that mean, a new engine? Does that mean distance, power, what?

JEFFREY LEWIS: Well, what it really means is know-how.

And so, ultimately, that will translate into distance and power. So, in the past, the North Koreans, by copying missiles, if we have asked this question can you build an ICBM, we have had to imagine how they could cobble together an ICBM using parts and pieces from other engines they have copied.

Now it looks like they actually have the design expertise to build this kind of missile themselves, and I think in the future that should lead us toward an ICBM.

JUDY WOODRUFF: So, as I said in the introduction, 500 miles, but the experts are saying it could potentially be 2,500 miles. I mean, what is the potential capacity of this?

JEFFREY LEWIS: Right.

Well, so what the North Koreans did was, they shot it almost straight up, because they didn't want to fire it at Alaska. They didn't want it to overfly Japan. And so, while it only traveled — sorry — I have to do kilometers — while it only traveled about 800 kilometers downrange, it went more than 2,000 kilometers up into space, which is much higher than, for example, the International Space Station.

So, if they had straightened it out, it would have been like a 4,500-kilometer range, which would be nearly an ICBM, but not quite.

JUDY WOODRUFF: So, that means they can reach where — could reach where?

JEFFREY LEWIS: That missile would just fall short of Alaska.

JUDY WOODRUFF: So, U.S. land, territory.

Is this — and your point is that this is — it's technology that the North Koreans, as far as we know, have only gained recently?

JEFFREY LEWIS: Well, that's right.

In the past, they have mostly copied other countries' engines, and so there's been kind of a problem with quality and a real limit on what they could do with that.

This is probably a breakthrough, in the sense that, now they have that design expertise on their own, they will be able to continually improve and make longer — longer-range missiles.

JUDY WOODRUFF: I was reading that this says a lot about their ability potentially to miniaturize a warhead, about the ability of the missile to survive reentry into the Earth's atmosphere, once it goes up into space, comes back down again. I'm assuming all of that is significant.

But they haven't perfected it yet. What are the hurdles that they still need to overcome?

JEFFREY LEWIS: Well, what they have done are test all of the parts and pieces.

So, for example, we have seen this new large engine. We have also seen North Koreans test a different engine that would work in an ICBM. We have seen them do ground tests of the — it's called a reentry vehicle. It's basically the ability to bring the warhead back into the atmosphere.

So, really, what North Korea has to do is put all those things together and test them at once. So, that's still in the future, but it's not very far in the future.

JUDY WOODRUFF: What do you mean not very far?

JEFFREY LEWIS: They could test an ICBM as soon as this year, although it's possible that they will take longer now that they're designing their own engines. They may wait and do it right.

But I would not — this is not a five- or 10-year problem. This is a one- or two- or three-year problem.

JUDY WOODRUFF: Hence getting the attention of U.S. officials and officials in the reason.

Just final quick question, Jeffrey Lewis. Are the North Koreans figuring this out because they have a bunch of smart scientists? Are they sitting around? Are they stealing this information from somewhere else? Do we know how they're doing this?

JEFFREY LEWIS: Well, in the past, they had a lot of help. And so we would see the North Koreans poking around in Russia and Ukraine looking for technology.

I think the reason this particular engine is important is because it really looks like something they designed themselves. So I think they have moved from the point where they are importing things and stealing information to actually designing their own engines. And that's a big step.

JUDY WOODRUFF: It certainly sounds like it.

Jeffrey Lewis with the Monterey Institute of International Studies, we thank you.

JEFFREY LEWIS: Thank you.