GEOFF BENNETT: With the war in Ukraine now well into its fourth year, Russian President Vladimir Putin has intensified attacks across the country.

But even amid the barrage, Ukraine says it's adapting, pushing back along parts of the front and carrying out increasingly sophisticated drone strikes deep inside Russia.

Special correspondent Simon Ostrovsky sat down with Ukraine's foreign minister to discuss the state of the war and the battlefield lessons Ukraine says are reshaping modern combat.

SIMON OSTROVSKY: As Russia falters on the Ukrainian battlefield, Moscow has attempted to rattle nerves in Ukraine with threats to renew attacks against the capital, including a warning to Washington to evacuate its diplomats from Kyiv.

Meanwhile, Ukraine has continued its campaign of long-distance strikes on Russian energy facilities, describing them as long-range sanctions designed to cripple Moscow's main source of revenue.

In an exclusive interview with "News Hour," Ukraine's Foreign Minister Andriy Sybiha had a warning for Russians, saying they were no longer safe anywhere in their vast country because of Ukraine's improved drone range and capabilities.

ANDRIY SYBIHA, Ukrainian Foreign Minister (through translator): We proved how effective we could be.

In Russia, there are no safe place.

We could attack them at a distance of up to 2,000 kilometers.

Even to conduct this so-called parade, Putin had to approach to allow to conduct this parade on the 9th of May.

SIMON OSTROVSKY: And Donald Trump put pressure, I think, on your country not to attack Moscow during the parade.

ANDRIY SYBIHA: We are not talking about any kind of pressure.

We have great cooperation with our American friends and we are thankful for their efforts.

Without the United States, it is not realistic to achieve tangible results in our peace efforts.

SIMON OSTROVSKY: Sybiha is keen to downplay any tensions with the United States, which he said Ukraine still relies on for air defense weapons, such as Patriot missiles, and intelligence on Russian targets.

ANDRIY SYBIHA: We are buying this type of weaponry from the United States, no delay, by the way, with the supply, despite the situation in the Middle East.

We have such an advantage that we could test our products immediately on the battlefield.

What does it mean?

It means highest quality.

It also means immediate feedback.

SIMON OSTROVSKY: Well we heard our president say that he didn't need any help from Ukraine.

Yet, recently, hasn't there been an agreement between your military and America's military?

ANDRIY SYBIHA: We have a pragmatic cooperation with our American allies.

We are ready to share with our experience, with our technologies.

Our position is clear.

We are open for this type of cooperation.

SIMON OSTROVSKY: But has an agreement been signed, a new agreement on defense technology cooperation?

ANDRIY SYBIHA: Not yet, but we are ready to propose.

And I am confident it will be our true contribution in American security.

We have now this experience, which is also needed for such great countries as the United States.

SIMON OSTROVSKY: We have seen reporting about the fact that the United States may have had to abandon a lot of its military positions in the Persian Gulf because of an inability to defend those bases against drone attacks from Iran.

Ukraine has a wealth of experience with interceptor drones, which are cheap.

And I think that's the sort of cooperation that you're talking about, and you're willing to share that with the United States.

ANDRIY SYBIHA: Absolutely.

And we already proposed to the Middle East countries our expertise.

Now we are a security partner for them.

And for us, this is also important.

SIMON OSTROVSKY: So is Ukraine selling interceptor drones to partners in the Middle East?

ANDRIY SYBIHA: This approach is not about selling, just selling a drone.

SIMON OSTROVSKY: Not just selling, but you are transferring equipment?

ANDRIY SYBIHA: We are talking about long-term arrangements, agreements.

SIMON OSTROVSKY: Do you feel you can still trust the United States and the White House in the way that Ukrainians once did?

ANDRIY SYBIHA: Our security and the security of the United States, the transatlantic security, they are indivisible.

Everything is interlinked.

And I think that strong Ukraine is also a national interest of the United States.

SIMON OSTROVSKY: Europeans talk about Ukraine less frequently as a case for assistance, and more frequently as an example of a military to follow.

Have you noticed a change in the way other countries look at Ukraine?

ANDRIY SYBIHA: Yes, definitely.

We became a security provider, security partner.

Our European allies now need Ukraine.

Ukraine, with its defense capacities, is an essential part of transatlantic security, and it is a smart approach to keep us in.

SIMON OSTROVSKY: Do you see Ukraine joining NATO and the European Union in the near future?

ANDRIY SYBIHA: Definitely.

Ukraine must and will become the member of E.U.

After the Hungarian elections, probably, we eliminated the most difficult political obstacle.

SIMON OSTROVSKY: Orban.

ANDRIY SYBIHA: Regime Orban.

So, yes, true, now we have the chance to speed up our efforts to become a full member of E.U.

SIMON OSTROVSKY: Prime Minister Viktor Orban's defeat in last month's election in Hungary cleared the last remaining barrier for Ukraine's E.U.

ascension negotiations.

ANDRIY SYBIHA: The most important now to end this war.

Ukraine wants to end this war.

We have doable proposals.

We are in the momentum to use our leverage to pressure Russia, not to ease sanctions, but, on contrary, to increase pressure on Russia and to raise the price of further aggression personally for Putin.

He must admit that he will never achieve his goals on the battlefield.

SIMON OSTROVSKY: Yesterday, the new head of British intelligence said more than half-a-million of Putin's troops have been killed in Ukraine since he invaded 4.5 years ago.

And with Ukrainian forces gaining back land in the east, Putin's goals on the battlefield seem further than ever from his grasp.

For the "PBS News Hour," I'm Simon Ostrovsky in Kyiv.