Ukrainian drone teams demolished a brigade of US Army tanks and armored vehicles during a live war game held this year—but the US soldiers were lucky enough to get “respawn” attempts while learning from the experience.

The semiannual military exercise, called Combined Resolve, gave the US military a firsthand taste of how modern drone warfare has evolved on the battlefields of Ukraine. The Ukrainian drone operators participating in the exercise were easily able to spot and destroy US armored vehicles by mimicking the actions of dropping bombs from above or moving close enough to simulate a kamikaze strike, according to US officials and a participant who spoke with The Wall Street Journal.

US armored vehicles were being destroyed so quickly that they were “respawned” and sent back into the simulated fray, a US official told The Wall Street Journal. The US troops who participated in the exercise—held in Germany from April 9 to May 10—were on rotational deployment from Fort Hood, Texas.

“Using the drones with the Army, it keeps everyone on edge,” according to an unidentified US Army soldier in a promotional video for Combined Resolve. “There is never a safe spot or safe moment in the game anymore.”

The participating troops hailed from the 3rd Armored Brigade Combat Team of the 1st Cavalry Division, which typically operates armored vehicles, like M1A2 tanks and Bradley infantry fighting vehicles.

But by repeating the training scenario throughout the two-week exercise, US Army troops got better at figuring out how to disperse and hide from the drones while using countermeasures such as electronic warfare.

The US military is not alone in learning such lessons from battle-hardened Ukrainian drone operators.

Ukrainian drone teams also participated in a Swedish-led military exercise for NATO, called Aurora 26, that was also held in May. A mock mechanized assault by NATO tanks and infantry fighting vehicles allowed Ukrainian drones to take out dozens of the attacking armored vehicles, which eventually forced planners to reset the war game, The Kyiv Independent reported.