JUDY WOODRUFF: We return to our top story, the upsurge in Taliban-driven violence in Afghanistan, nearly 15 years into the American involvement there.

Smoke over the Kabul skyline signaled the capital was under attack.

AHMAD NAVID, Witness (through interpreter): It was a big blast. Dust covered all the area. I wasn't able to see what was happening. Later, I saw lot of damage.

JUDY WOODRUFF: One insurgent blew up a truck bomb outside a security agency that protects top officials. A second attacker ran into the compound and started shooting.

GEN. ABDUL RAHMAN RAHIMI, Kabul Police Chief (through interpreter): After the car bomb exploded, a suicide bomber was trying to enter the building. He came under fire from inside the building, as well as from police forces who were outside, who didn't give him the chance to enter. He was killed.

JUDY WOODRUFF: The attack caused extensive damage just a few hundred yards from the presidential palace. Meanwhile, fighting continued in the northern part of the country, where government forces around Kunduz have battled this week to repel a Taliban assault.

Last year, the militants captured the city and held it for three days before Afghan forces backed by U.S. airstrikes drove them out. But Afghanistan's chief executive, Abdullah Abdullah, said Kunduz and Kabul show the Taliban's latest spring offensive has failed.

ABDULLAH ABDULLAH, Chief Executive, Afghanistan (through interpreter): They were defeated all over the country after they carried out their attacks and have suffered lots of causalities. So, by carrying this suicide attack, they wanted to take revenge.

JUDY WOODRUFF: Still, by most reckoning, the Taliban is at its strongest in years, likely a concern for President Obama, when he reversed course last fall, and announced the U.S. will keep 10,000 troops in Afghanistan through this year, drawing down to 5,500 in 2017.

For more on today's attack in Kabul, and what it says about the overall security situation in Afghanistan, we turn to Seth Jones. He's director of the International Security and Defense Policy center at the RAND Corporation. He's written extensively about Afghanistan, and in 2011 was a special adviser to U.S. special operation forces there.

Seth Jones, welcome back to the program.

So, what does this attack today in Kabul say about the Taliban? Is it stronger than it's been, or, as Abdullah Abdullah says, is what it's doing failing?

SETH JONES, RAND Corporation: Well, Judy, I think what it shows is the Taliban does have the ability to conduct attacks in most any parts of the country.

And they actually said this in their Twitter feeds today and in their Internet announcements after the attack of the purpose of doing this. At the same time, it's probably also worth knowing that the Taliban doesn't control urban terrain, like ISIS does in Iraq, for example. They don't control Kabul. They don't control any major provincial capitals.

So these kind of urban attacks are done more for psychological operations, rather than control of territory.

JUDY WOODRUFF: Well, what's the distinction, though? You say they don't control urban areas, but they're able to pull off something like this, almost 30 people killed, hundreds badly hurt.

SETH JONES: Yes. What it shows, they do control a fair amount of rural terrain. They also have cell structures that operate in cities. So while the government controls most of the urban terrain in cities like Kabul, the Taliban does have an ability to push in resources and conduct attacks.

And it certainly has an effect on the population there, which believes the government can't secure it at all times.

JUDY WOODRUFF: And so that psychological effect, why isn't that the same or almost the same as having actual control?

SETH JONES: Well, it's different because the Taliban does a lot. It administers justice in areas that it controls. It taxes the local population.

It has a political structure, almost a political state apparatus, in areas that it controls. It doesn't have that in cities like Kabul. What it has is really a military and intelligence infrastructure, but it wants the political architecture to go with that. So this — it is part of a longer-term campaign.

JUDY WOODRUFF: What does this say, Seth Jones, about the standing of Afghan security forces, which we know the U.S. has been trying to build up for years now?

SETH JONES: Look, there are plenty of challenges with the Afghan national security forces. The higher-end forces that responded to this today, the intelligence forces, the Afghan commandos, the Qataha (ph), some of the higher-end army forces, are pretty good.

But the general state of the police and a lot of the army kandaks are of mixed quality. I think the problem that we're seeing is, they're not very proactive in pushing out against the Taliban in rural areas. And so the fight is now coming to them in the cities.

JUDY WOODRUFF: How do you assess what the U.S. is doing? We know the president decided to keep American troops in Afghanistan longer, but what is the — what role is the posture — is U.S. posture playing right now in this battle between Afghans — the Afghan government and the Taliban?

SETH JONES: Well, first of all, the U.S. president has said that the number of troops, it will continue to come down through January of 2017. So now we're roughly 10,000. He said they're going to go down to about 10,000 — about 5,500.

He's also restricted the ability to conduct strikes against the Taliban a few other groups like the Haqqani Network without — unless there's a good example of those forces conducting attacks against Americans. So, there are also limits on what the U.S. can do training out in the field.

So, the U.S. has sort of limited its ability to impact this, except in response to these kinds of attacks.

JUDY WOODRUFF: Well, we are continuing to watch the story.

Seth Jones, we thank you for joining us.

SETH JONES: Thanks, Judy.