In November last year, Brig. Gen. Kyrylo Budanov sounded the alarm. Vladimir Putin, Budanov told the Military Times, was using the massive Zapad 21 exercises in western Russia and Belarus as a screen for a planned invasion of Ukraine. A day later, Bloomberg reported that US intelligence sources were saying that Russia was preparing for a multipronged push into Ukraine.

At the time, Putin’s spokesperson denounced Budanov’s claims as “hysteria,” and much of the rest of the world was disinclined to believe them—that is, right up until the morning of February 24, when Russia’s invasion of Ukraine began.

As the head of the defense intelligence agency of Ukraine—the GUR—Budanov is a member of a new generation of Ukrainian defense officials who model themselves on NATO officers rather than their Soviet predecessors. He came of age after the fall of the USSR, working with Ukraine’s defense intelligence agency on operations in Russian-occupied Crimea in the middle of the last decade. In 2019, he was targeted by an assassin who tried to bomb his car. Budanov’s appointment in 2020 by President Volodymyr Zelenskyy was criticized by people who said he was too young—Budanov is 36. Once in office, he went about his work building links with intelligence agencies from the United States to Turkey, and focusing on making Ukraine’s intelligence service less hierarchical and more horizontally integrated. The head of the United States’s National Security Agency recently said that since the beginning of the war intelligence sharing with Ukraine had been “revolutionary.”

Budanov and I spoke the other day over an encrypted line about the war and some of its major themes: He has vowed to stay in Kyiv and carry out his duties. I had been placed in contact with Budanov by a filmmaker who is making a documentary about the war. I later fact-checked the interview with his staff using an official GUR e-mail. Speaking on the record in Ukrainian through a translator with him in Kyiv, Budanov told me that, despite the Ukrainian military’s relative success at holding off the Russians, “the situation is very difficult. We have large Russian forces on our territory, and they have encircled the cities of Ukraine. As for the prospects of peace, despite the negotiations, they still remain vague and unpredictable.”

He was disinclined to trust the Russians—“the Russian side has never been predictable in a case of negotiations”—and struck a defiant note: “Our country understands with whom we are dealing, and we don’t expect any miracle here. We are dealing with an army of criminals, of looters, of mercenaries, and we are ready to fight and win.”

“Russian command has made miscalculations many times, and we use these miscalculations,” Budanov said. “The Ukrainian army has shown that the Russian army as the second army in the world is a big myth, and it’s just a medieval concentration of manpower, old methods of warfare.” At the end of the war, he hopes Ukraine will finally be able to deploy a fully functional air defense system, and seek international guarantees that will assure its peace.

One of the keys to the Ukrainian forces’ effectiveness in the current conflict, Budanov said, has been intelligence gathering. He averred that from the beginning, the Ukrainians had been prepared. “We have lots of informers within the Russian army, not only in the Russian army, but also in their political circles and their leadership,” Budanov told me. “In November, we already knew about the intentions of the Russians, and you can see that everything came through. As for the date, it changed several times.” Budanov said that this intelligence meant the Ukrainians were prepared for an invasion.

Budanov also told me that the Ukrainians were tracking Chechen forces fighting for Russia on the territory of Ukraine using their cell phones and human intelligence sources. (The Chechens appear to have problems with operational security—the BBC acquired private messages that Ramzan Kadyrov, the Chechen leader who is a close Putin ally, had made before the invasion bragging to an associate about the upcoming war.)

In the Russian world, Chechens have the reputation of being particularly effective soldiers. Throughout the invasion, Kadyrov has released videos on his Telegram channel of bearded Chechen troops in Ukraine engaging in brutal firefights and conducting activities on Ukrainian soil. Some Ukrainians have traced locations in these pictures of Kadyrovtsi, as Kadyrov’s men are known, and highlighted that they are in fact in Belarus, far from the front.

Budanov said that his department has tracked a contingent of around 25,000 Chechens since the beginning of the war. “We have many informers inside the Chechen ranks. As soon as they start preparing any operation, we know that from our informants,” he said. “When the war started, Russia underwent lots of casualties, and most of these people didn’t even manage to approach Kyiv.” He pointed out that Ukrainian special forces had engaged with a group of looting Chechens near Kyiv the day before we spoke that was only two strong. “We’ve never seen more 20 or 30 Chechens in one place. The concentration is very low.”

The war has entered a new phase, Budanov said, one in which the Russians have begun to shell Ukrainian cities and avoid ground clashes (“Russians are cowards because they bombarded and shelled our peaceful people, our hospitals, our drama theatres, maternity houses”). He compared the Ukrainians to Spartans who at Thermopylae stood and fought without bows and arrows, though he was confident that the Ukrainians would not share the Spartans’ fate of annihilation by an overwhelmingly powerful army.

Budanov and I also spoke about the unseen war that is happening over computer networks, and how hackers are now vigorously involved on both sides. This phase of the war began nine days before the invasion, on February 15, when Russian hackers launched an attack on government agencies and Ukrainian banks (“The key issue for the Russians was the disruption of work and the spread of panic”). Recently, he said, Ukrainian intelligence has monitored phishing attacks on his government’s officials by the Belorussian hacking group Ghostwriters, and the Russia-affiliated Fancy Bear group, which also has been blamed for orchestrating the hack of Democratic party e-mails during the 2016 election. Ukraine, he said, has mobilized a large volunteer force of hackers who are targeting their own attacks on Russia’s digital infrastructure.

One of the key components of Budanov’s job has been to organize a force of guerrillas who will stay behind Russian lines. He wouldn’t say much about the force, except that it is “a very large number of people,” raising the prospect of a drawn-out insurgency like that in Afghanistan or Vietnam. He mentioned that hunters had been drafted into the group, and I thought about the Ukrainian woodsman who blew himself up near Chernihiv with a grenade rather than hand over a list of local hunters to Russian troops. “Our warriors, our servicemen, even our hunters will start hunting the aggressor, the Russian forces, with their rifles in the forests,” he said. “I should say that soon the spring will come, our forests will become green, and a real hell will open up for the aggressor.”