GEOFF BENNETT: President Biden will meet without going NATO Secretary-General Jens Stoltenberg tomorrow.

They're expected to discuss Russia's ongoing invasion of Ukraine and efforts to persuade fellow NATO member Turkey to back off blocking Sweden from joining the alliance.

Stoltenberg's tenure as NATO leader ends in September.

And a number of countries are competing for who will replace him.

Joining us now is the NATO Secretary-General, Jens Stoltenberg.

Thank you for being with us.

JENS STOLTENBERG, NATO Secretary-General: Thanks so much for having me.

GEOFF BENNETT: Ukrainian President Volodymyr Zelenskyy has been imploring NATO leaders to put Ukraine on a concrete path to membership.

He has said that he would not appear next month at the NATO summit without a clear signal about Ukraine becoming a full member of that alliance.

Since there is no consensus among member nations on this matter.

What are you prepared to give Ukraine?

What sort of promise, what kind of commitment?

JENS STOLTENBERG: So, first and foremost, the most important thing that will happen at the NATO summit in Vilnius in July is that NATO allies will express strong support to Ukraine, not only words, but also in deeds, because I'm absolutely certain that our NATO allies will make new announcements of significant military support to Ukraine and to promise to sustain and step that up, because we will make absolutely clear that we are there to support Ukraine for as long as it takes.

Then, on the issue of membership, yes, there are consultations going on among allies, and we have not concluded them.

It's too early to preempt the concrete outcome, but allies agree on a lot.

We agree that NATO's door is open, as we have demonstrated with Finland and Sweden for new members.

We also agree that Ukraine will become a member of this alliance.

This has been stated many times by NATO, last time at a summit last year.

And then, thirdly, we agree that it's for Ukraine and the 31 NATO allies to decide when the time is right for Ukraine to become a member.

It's not for Russia.

Russia doesn't have a veto.

So I'm confident that, at the NATO summit, there will be a strong message on Ukraine, because we need to stand by Ukraine.

GEOFF BENNETT: When you say you're confident that Ukraine will become a full member of the alliance, how do you respond to what President Zelenskyy told The Wall Street Journal?

He said: "How many lives of Ukrainians are worth the phrase Ukraine will be in NATO after this war, after it's safe?"

How do you respond to that?

JENS STOLTENBERG: Well, I understand that he's pushing for a clear timetable for NATO membership.

At the same time, I believe it's not possible to give precise dates when we are in the midst of a war.

And I think also that all allies will also very clearly express that the most urgent task now is to ensure that Ukraine prevails as a sovereign, independent nation, if we need to provide more military support, because, unless Ukraine prevails, then there's no membership to be discussed at all, because it's only a sovereign, independent, democratic Ukraine that can become a NATO member.

I also expect that we will agree a multiyear plan, program for how to ensure the transition of the Ukrainian armed forces from the old Soviet standards, doctrines to modern NATO standards and doctrines, and to ensure that they are fully interoperable with NATO and that will also move them closer to membership.

GEOFF BENNETT: Ukraine's long-anticipated counteroffensive is now under way.

In NATO's view, what does a successful counteroffensive look like?

What's the metric of success?

JENS STOLTENBERG: Well, the aim is, of course, to liberate Ukrainian land and to send a message to Moscow that they will not win on the battlefield, Russia will not achieve its goals.

And, at some stage, Russia needs to realize it has to sit down and negotiate a just and lasting peace for Ukraine.

It is encouraging to see that the Ukrainians are making progress, but, of course, wars are unpredictable.

So it's not possible now to say when and how the war will end and, of course, to predict the exact outcome of this offensive.

GEOFF BENNETT: Well, Ukraine says success is taking back the Donbass and Crimea.

Is NATO prepared to support Ukraine that far?

JENS STOLTENBERG: So, we support Ukraine because we need to remember that this is -- what this is.

This is a war aggression.

Russia has invaded another country.

It violated international law by sending in tens of hundreds of thousands of soldiers and armor and missiles against a sovereign country in Europe.

NATO allies -- the right for self-defense is enshrined in the U.N. Charter.

And what NATO allies do is that we support Ukraine in upholding that right.

That doesn't make NATO a party to the conflict.

And we will support Ukraine for as long as it takes.

GEOFF BENNETT: China has remained conspicuously close to Russia as this war has progressed.

How is the alliance planning to confront the challenges posed by Beijing?

JENS STOLTENBERG: It demonstrates that security is not regional anymore.

It is global.

What happens in Europe matters for Asia, and what happens in Asia matters for Europe.

NATO will remain an alliance of North America and Europe, but this region, North America and Europe, faces global threats, and that includes the fact that China is investing more and more in advanced military capabilities, nuclear weapons, and also trying to threaten neighbors around the world.

So, this -- and then, of course, the fact that China and Russia are coming closer and closer,they just conducted a big naval exercise together.

We see more Russian and Chinese joint naval and air patrols.

This makes it just more important that NATO's alliance also addresses the challenges to our security posed by China and that we -- we stand together in addressing also the security consequences of China.

GEOFF BENNETT: To your point about the region facing persistent threats, what about Sweden?

What are the prospects for Sweden to join the alliance?

You were just at Erdogan's inauguration, one of the few Western leaders to go there.

You met with him.

Will Turkey allow Sweden to become a member of NATO by next month's summit?

JENS STOLTENBERG: I'm confident that Sweden will become a full member.

And it's possible that that can happen by the NATO summit in Vilnius next month, but I cannot guarantee that.

What I can say is that I met President Erdogan recently in connection with the inauguration.

We had a very good meeting.

And we agreed to convene what we call the Permanent Mechanism, which was something we established last year between Finland, Sweden and Turkey.

They're actually meeting this week in Turkey with NATO to address the differences that still exist to ensure that we make progress on making Sweden a full member of our alliance.

Sweden has come a long way, because all allies invited them also Turkey last year at our summit in Madrid.

And, since then, they have obtained a status that makes them now integrating more and more into NATO structure and at the NATO table.

But we need full ratification.

And we're working hard to make that happen as soon as possible.

GEOFF BENNETT: In the 30 seconds we have left, we should note that you have led NATO since 2014.

You have, in the past, extended your term.

If you're asked to extend your term yet again, will you?

JENS STOLTENBERG: I'm absolutely confident that this great alliance will be able to find a great successor.

And my focus now is on leading the alliance until my tenure ends this fall.

We're in midst of a war in Europe.

And I'm focused on that.

And then I'm confident that the 30 allies, 31 allies, will find a successor to replace me.

GEOFF BENNETT: I hear your confidence, but I didn't hear a no.

JENS STOLTENBERG: No, but, I mean, I have no other plans than to end my tenure as secretary-general.

I have been extended three times already.

I'm here now.

The plan was to be here for four years.

I have been there for nine years.

So, I think the good thing for everyone is now to have another person at the helm of the alliance.

My focus is on being here, leading the alliance until there's new person in place.

GEOFF BENNETT: Jens Stoltenberg is the NATO secretary-general.

Thanks for your time this evening.

We appreciate it.

JENS STOLTENBERG: Thank you so much.