Ukrainian forces say they used carrier drones to drop armed ground robots more than 10 miles behind Russian lines during “Operation Vivaldi,” a campaign that ran from May through late September.

According to Ukraine’s Third Army Corps, the operation involved more than 15,700 missions and helped retake roughly 48 square miles of territory in the Donetsk region, including five villages and three other settlements. Ukrainian officials also claimed that about 3,000 Russian troops were killed, though those battlefield casualty figures have not been independently verified.

The operation marked a significant expansion in Ukraine’s use of unmanned ground vehicles, or UGVs. The robotic platforms can be equipped with heavy machine guns or explosives and were deployed in areas where sending Ukrainian soldiers would have exposed them to additional danger.

Gen. Andrii Biletskyi, commander of Ukraine’s Third Army Corps, described the tactic as a first-of-its-kind battlefield maneuver, saying Ukrainian forces were able to deliver ground robots into positions where Russian forces were not expecting an attack from the ground.

The missions required coordination among several types of Ukrainian military equipment. Carrier drones transported the ground robots behind Russian positions while electronic warfare systems attempted to disrupt Russian surveillance drones. Ukrainian aircraft and artillery then helped keep Russian forces occupied while the carrier drones moved into position, often at night.

“The enemy expects the threat from the sky, not the ground,” Biletskyi said, according to accounts of the operation.

A commander identified by the call sign Darwin said the unmanned systems offered an important advantage because Ukraine could risk losing a machine without putting a soldier in the same position.

The operation also highlighted the increasing importance of electronic warfare and unmanned systems in the conflict. Ukrainian commanders said Russian forces initially struggled to believe that the ground robots could have traveled such a long distance behind their lines.

Mykola Zinkevych, another Ukrainian commander involved in the operation, said an intercepted Russian exchange showed one officer dismissing the possibility that Ukrainian robotic vehicles had reached the area.

Ukrainian officials argue that the development of ground-based robotic warfare could eventually reduce battlefield casualties by allowing machines to perform some missions previously assigned to troops.

A 23-year-old Ukrainian deputy commander known by the call sign “Bar” said the robots require neither food nor water and can be sent into dangerous positions without putting another soldier at risk.

“If UGVs had been used earlier in the war,” he said, “a great number of my friends would still be alive.”

The operation reflects how the war in Ukraine continues to accelerate the use of unmanned technology, with both sides increasingly relying on drones, electronic warfare and robotic systems to strike targets while limiting the exposure of human troops.