Inside Operation Vivaldi: How Ukraine sent explosive robots behind Russian lines

According to the Ukrainian military, the operation recaptured 277 square kilometers (107 square miles) of territory and took nearly 300 Russian soldiers prisoner.

Kupriianov, who received Ukraine's highest state honor, Hero of Ukraine, in September, said the operation disrupted Russian plans to advance toward the Ukrainian-held cities of Sloviansk and Kramatorsk.

"We disrupted Russia's plan to seize all of Donbas," he said. "Now they're forced to play by our rules."

A robot carrying another robot

One of the operation's most unusual tactics involved using a large bomber drone to transport a small unmanned ground vehicle (UGV) carrying explosives.

The aerial drone dropped the vehicle behind Russian positions. The ground robot then drove to its target and detonated.

"It's basically a robot carrying a robot," Kupriianov said.

He said Russian troops were shocked to encounter Ukrainian ground robots behind their lines, apparently unable to understand how the vehicles had crossed the front.

Kupriianov described the tactic as a first for the corps and said it could become more widely used.

Ground robots were also employed as mobile weapons platforms, carrying heavy machine guns or automatic grenade launchers.

But their most important role was logistical.

According to Kupriianov, UGVs now handle around 80% of frontline logistics for the Third Army Corps, transporting ammunition, food and wounded personnel.

He cautioned against treating the technology as a weapon capable of winning battles on its own.

"It doesn't win the war by itself," he said.

And despite the growing role of unmanned systems, he rejected the idea that infantry could be eliminated from warfare.

"You can't do without infantry. Maybe in a thousand years," he said.

Keeping an offensive secret for four months

Operation Vivaldi was prepared under strict information controls, with details shared among troops only when necessary.

Kupriianov said even some participants learned the operation's final objective only toward its conclusion.

The Third Army Corps also contacted Ukrainian and Western open-source intelligence (OSINT) analysts whose monitoring could have exposed troop movements.

"The overwhelming majority cooperated and did not publish that information," he said.

He argued that such information discipline was crucial because soldiers can inadvertently disclose operational details.

Preparations included training infantry, drone operators and artillery crews to operate while advancing rather than defending fixed positions.

Unlike defensive operations, he explained, an offensive requires personnel and equipment to move repeatedly, establish new positions and maintain supplies under fire.

Cutting off Russian troops

Kupriianov said the offensive initially focused on isolating Russian infiltration groups that had moved behind Ukrainian positions.

Such groups can attack Ukrainian drone teams, mortar crews and supply vehicles, making it difficult to distinguish controlled territory from contested ground.

Ukrainian forces cut these groups off from reinforcements and supplies before clearing them from the area, he said.

The commander described Russian troops running short of ammunition, food and water.

"During Vivaldi, Russian groups ate animals and drank from puddles," he said.

He also claimed that inaccurate reporting within the Russian chain of command contributed to the operation's success.

Russian units had allegedly reported occupying positions they did not actually control, leaving commanders with a distorted picture of the battlefield.

When Ukrainian forces advanced, Kupriianov said, Russian troops struggled to report their real positions without exposing earlier false claims.

Rebuilding a brigade before attacking

Kupriianov said the offensive also reflected organizational changes within the 125th Brigade, which had previously suffered severe setbacks.

After the unit joined the Third Army Corps, commanders reorganized personnel, changed appointments, improved training and integrated new equipment.

He said the brigade had not initially been ready to conduct offensive operations.

Only after restructuring, joint training and lower-intensity combat experience did commanders consider it capable of advancing.

"Everything is decided by people and a healthy system," he said.

Although the corps invested heavily in drones, artillery and other equipment, Kupriianov argued that technology alone was insufficient without effective leadership and properly trained personnel.

Why he believes Ukraine must keep attacking

The commander rejected the argument that remaining on the defensive necessarily saves Ukrainian lives.

Casualties occur in both offensive and defensive operations, he said, arguing that the decisive question is which side controls the initiative.

"There's an illusion that if we settle into a purely defensive posture, we'll save personnel. That's nonsense," Kupriianov said.

"Either the enemy imposes the initiative, or we do."

He acknowledged that Ukraine faces serious manpower shortages, even as its technological capabilities and battlefield experience have expanded.

His assessment of Operation Vivaldi's strategic effects and casualty balance represents his perspective as a participating commander; independent assessments of the full operation's outcomes were not provided in the interview.

For Kupriianov, the lesson is that new technology, effective organization and offensive action must work together.

"We will win through offensive operations and the liberation of territory," he said.