KYIV, Ukraine — For Ukraine's counteroffensive to progress faster, Gen. Valery Zaluzhny, the top officer in Ukraine's armed forces, says he needs more - of every weapon. And he is telling anyone who will listen, including his American counterpart Gen. Mark A. Milley as recently as Wednesday, that he needs those resources now.

In a rare, wide-ranging interview with The Washington Post, Zaluzhny expressed frustration that while his biggest Western backers would never launch an offensive without air superiority, Ukraine still has not received modern fighter jets but is expected to rapidly take back territory from the occupying Russians. American-made F-16s, promised only recently, are not likely to arrive until the fall - in a best-case scenario.

His troops also should be firing at least as many artillery shells as their enemy, Zaluzhny said, but have been outshot tenfold at times because of limited resources.

So it "pisses me off," Zaluzhny said, when he hears that Ukraine's long-awaited counteroffensive in the country's east and south has started slower than expected - an opinion publicly expressed by Western officials and military analysts and also by President Volodymyr Zelensky, though Zaluzhny was not referring to Zelensky. His troops have gained some ground - even if it's just 500 meters - every day, he said.

"This is not a show," Zaluzhny said Wednesday in his office at Ukraine's General Staff headquarters. "It's not a show the whole world is watching and betting on or anything. Every day, every meter is given by blood."

"Without being fully supplied, these plans are not feasible at all," he added. "But they are being carried out. Yes, maybe not as fast as the participants in the show, the observers, would like, but that is their problem."

For the past 16 months, Zaluzhny, 49, has had the monumental challenge of leading Ukraine's military against a larger, better-armed Russian force that still occupies about one-fifth of his country, even after successful counteroffensives last fall. He has managed it, in part, by transforming his soldiers into a modern, nimble force, schooled in NATO tactics, and by shedding the overly centralized Soviet-style command structure that was still in place when he first entered training.

The questions that weigh on him daily: When will Ukraine's Western partners provide the arms he needs, particularly more ammunition and the F-16s? And how can he be expected to get the job done without them?

Zaluzhny said he relays his concerns to Milley, whom he has grown to deeply admire and considers a friend, several times per week in conversations that can last hours. "He shares them absolutely. And I think he can help me get rid of those worries," Zaluzhny said, adding that he told Milley on Wednesday how many more artillery shells he needs per month.

In these conversations, Zaluzhny is frank about the consequences: "We have an agreement: 24/7, we're in touch. So, sometimes I can call up and say, 'If I don't get 100,000 shells in a week, 1,000 people will die. Step into my shoes,'" he said.

But "it's not Milley who decides whether we get planes or not," Zaluzhny said. "It's just that while that decision is being made, in the obvious situation, a lot of people die every day - a lot. Just because no decision has been made yet."

While F-16s will eventually arrive, following President Biden's decision in May to back an international plan to train Ukrainian pilots and send the planes, Ukraine's strained ammunition resources pose a different challenge. In February, NATO Secretary General Jens Stoltenberg warned that the "current rate of Ukraine's ammunition expenditure is many times higher than our current rate of production." That means the shells Zaluzhny said he needs could become even scarcer the longer the war lasts.

Ahead of the long-planned counteroffensive, Ukraine for the first time received Western battle tanks, including German-made Leopards and infantry fighting vehicles. Moscow's troops have established a land corridor between mainland Russia and Crimea, the Ukrainian peninsula illegally annexed in 2014 where Russia has several military installations. Severing that link would deal a significant blow to Russia's ability to resupply its forces.

Those tanks and fighting vehicles debuted on the battlefield when the counteroffensive kicked off earlier this month. Several have already been destroyed, Zaluzhny acknowledged, adding that "we didn't get Leopards to ride in parades or have politicians or celebrities take pictures with them. They came here for the war. And a Leopard on the battlefield is not a Leopard but a target."

Ukraine has not yet launched the main thrust of its counteroffensive, analysts say. Not all of its specially-prepared forces have been committed to the front line, and those that have still seem to be probing for weak spots in Russia's defenses. Roughly 50 square miles in total have been liberated, Ukrainian officials have said.

But Zaluzhny also pointed to NATO forces' own doctrine - which parallels Russia's, he said - that calls for air superiority before launching ground-based deep-reaching operations.

"And Ukraine, moving to offensive operations, should follow which doctrine?" Zaluzhny said. "NATO's? The Russian Federation's? Or is that none of your business? 'You have your own doctrine. You have tanks, you have some cannons, you have some [fighting vehicles]. You can do it.' What is that?"

In his command post, Zaluzhny has a screen that shows him everything in the air at any given moment - the aviation from NATO countries at Ukraine's western border, his own planes in the sky over Ukraine, and Russia's on the eastern edges. "Let's just say the number of aircraft that are on duty near our western borders is twice as much as the number of Russian aircraft devastating our positions. Why can't we take at least a third of it from there and move it here?" Zaluzhny asked.

Because Russia's more modern fleet of Su-35s have a far superior radar and missile range, Ukraine's older jets cannot compete. Troops on the ground are easily targeted as a result.

"Nobody is saying that tomorrow we should rearm and get 120 planes," Zaluzhny said. "Why? I do not need 120 planes. I'm not going to threaten the whole world. A very limited number would be enough. But they are needed. Because there is no other way. Because the enemy is using a different generation of aviation. It's like we'd go on the offensive with bows and arrows now, and everyone would say, 'Are you crazy?' But with this question, 'No, no.'"

If anyone thinks that Ukraine's counteroffensive got a lucky boost last weekend when Wagner chief Yevgeniy Prigozhin led a mutiny of mercenary forces on an assault toward Moscow before halting the advance, Zaluzhny is not so sure. Prigozhin's Wagner forces had already exited the front line, after claiming the eastern city of Bakhmut a month ago, Zaluzhny said, so there was no noticeable change on the battlefield as the rebellion took place.

"We didn't feel that their defense got weaker somewhere or anything," he said.

The Wagner fighters who do not want to stay in Russia or sign defense contracts with Russia's Defense Ministry will have the option to join Prigozhin in Belarus, Russian President Vladimir Putin said. But while some of the mercenaries might be leaving the battlefield, where Ukraine's commanders often praised their effective - albeit brutal - tactics, Zaluzhny might now have to consider a new, additional threat to his northern border as some of the fighters relocate there.

"I have a lot of fears, and Wagner is among them‚" Zaluzhny said. "And they're not the only ones. If we start talking about it now, my head will spin. ... Our task is to prepare for the worst and most possible scenarios. And we will try to minimize the possible consequences of what could be."

One worst-case scenario Zaluzhny must consider is the threat that Putin might deploy a nuclear weapon. And Zelensky warned last week that Ukrainian intelligence received information that Russian forces were preparing a "terrorist act with the release of radiation" at the occupied Zaporizhzhia nuclear plant, Europe's largest atomic power station.

Does that give Zaluzhny pause from trying to retake control of the plant as part of Ukraine's counteroffensive?

"It doesn't stop me at all," Zaluzhny said. "We are doing our job. All these signals come from outside for some reason: 'Be afraid of a nuclear strike.' Well, should we give up?"

Kostiantyn Khudov contributed to this report.