HARI SREENIVASAN: Defense chiefs and other leaders from more than 30 countries are here in Washington for two days of meetings on the war against ISIS in Iraq and Syria.

The summit comes as ISIS loses territory in both countries, but the group and its followers lash out with terrorist strikes globally.

Meantime, there is continuing turmoil in Turkey, which borders both Syria and Iraq, after Friday's coup attempt.

For more on all of this, I spoke a short time ago with Michael Fallon, the United Kingdom's defense secretary.

Defense Secretary, welcome.

MICHAEL FALLON, United Kingdom Defense Secretary: Thank you, Hari.

HARI SREENIVASAN: First off, right now, we're hearing that the Turkish president has declared a state of emergency for another three months. This comes in a week where there has been a significant purge of people who might have been in opposition to him. Is Turkey still a reliable ally in NATO?

MICHAEL FALLON: Well, yes, it's still a key ally in NATO. It's a cornerstone of NATO. It's very important in the southeast corner of NATO to have Turkey there as a longstanding member.

It has formidable armed forces. And it's helping us fight ISIL as well in the Middle East. So, Turkey is important.

Now, it's obviously concerning that there's been this coup. And we're particularly concerned that Turkey keeps to the path of respecting human rights when it's dealing with the aftermath of the coup.

HARI SREENIVASAN: And does what's happening now compromise your ability to fight ISIS together with Turkey?

MICHAEL FALLON: Well, Turkey's made it clear that this doesn't affect their commitment to the fight against ISIL. We want to seal that border with Syria to stem the flow of foreign fighters.

And they have every interest in not having ISIL flourish on their doorstep.

HARI SREENIVASAN: Now, you're here for a series of conversations among defense secretaries and other world leaders on what to do in this fight. What is the United Kingdom prepared to do? What more are you prepared to do?

MICHAEL FALLON: Well, we're already playing the second part, after the United States, in this fight. We have carried out the second highest number of airstrikes.

We provide a large portion of the surveillance through aircraft ahead. And we have trained around 19,000 Iraqi and Kurdish troops, specialist training in how to deal with improvised explosive devices. So we're playing a big part in this. And we have announced recently that we're stepping up, putting more troops in, as the United States has asked every member of the coalition to do.

We are doubling the number of troops we have in Iraq itself, so that they can do more training, to really pick up on the momentum there is now. ISIS is being pushed back along the Tigris and the Euphrates. Towns and cities are being liberated. And we want to keep that momentum up.

HARI SREENIVASAN: But when you think of fighting wars as a defense secretary, how do you deal with the shift that's happened in your enemies? We're no longer fighting enemies who are on a battlefield wearing a uniform with certain colors on the other side of a line. Right?

But we have shifted to an insurgency strategy. And then now it seems, with the attacks that have been happening all through Europe, these are lone wolves, self-radicalized. And it somehow falls on your doorstep to say, let's keep the country safe.

MICHAEL FALLON: You're right. There is no front line in these conflicts anymore.

So this requires new tactics. You need to deal with their hybrid warfare, the kind of messages they're pumping out to sustain this very poisonous ideology. And then you need to deal with them where they have captured particular cities and they're imposing barbaric punishments on the citizens or imposing very high taxes.

So you need to deal with all these things. In the end, these things can only be done locally. They have to be won by local forces with security provided by the government in that country. Now, we can help. We can help with airpower, with technology, with training, with resources, help to stabilize these countries once they have been liberated.

But, in the end, the fight has to be on the ground by local forces that can retain the hearts and minds of the people that they're freeing.

HARI SREENIVASAN: Now, Britain went through a big decision-making process just a few weeks ago. Before that decision, you were a remainer. You wanted to stay in the E.U., it's no secret. You said during that time that U.K.'s departure would actually weaken Europe, it would strengthen Russia's hand.

Here we are, after the vote. Your thoughts?

MICHAEL FALLON: Well, NATO is the — the North Atlantic alliance is the principal security that we have that Britain is part of in Europe. And we have added more troops to the eastern border of NATO. We have stepped up to that.

Being inside the European Union gave us another lever. It was the union, not NATO, for example, that imposed sanctions on Russia, and we will continue in the remaining years we're inside the European Union to keep those sanctions up, to keep the pressure up on Russia.

I would rather we would have stayed. But the people have decided. We have had the vote now. And what we have to do is make a success of leaving the European Union, develop new relations with Europe, ensure our trade is protected, and to continue to play our part in the security of Europe, which we're doing through a greater commitment to NATO and more work with our key allies, like the United States.

HARI SREENIVASAN: Just in the last few weeks, we had a series of reports coming out of Eastern Europe on how NATO is preparing for the possibility of Russian aggression in places like Poland, places like Estonia.

What happens if Estonia raises its hand and says, NATO, I need help right now? How likely is the U.K. to want to help a member of the E.U. that also might may be a member of the NATO alliance?

MICHAEL FALLON: Well, all members of NATO are committed to help each other.

And, in fact, the Baltic states, including Estonia, have put their hands up and said, we want more reassurance. We have got Russia conducting large-scale exercises right on their doorstep, flying planes over the Baltic, and intimidating them through hybrid and social media.

So, we are stepping forward, as one of the four countries deploying a new forward presence, an entire battalion in Estonia from next year, with French and Danish troops added to it. The United States is doing the same in Poland itself. So we're all helping there to give more reassurance on the on the eastern side of NATO and making it very clear to Russia that, if they attempt to intervene in a NATO country, in the way that they did in Ukraine, which is outside NATO, then there will be consequences.

HARI SREENIVASAN: All right, Defense Secretary Michael Fallon, thanks for joining us.

MICHAEL FALLON: Thank you.