By Alistair MacDonald, Lara Seligman and Daniel Michaels

U.S. Army troops faced off against Ukrainian drone operators at a military exercise in Germany earlier this year. It didn't go well for the Americans.

During the exercise, called Combined Resolve, Ukrainian drone units easily spotted and defeated U.S. troops and armored vehicles on rotation from Fort Hood in Texas, according to people familiar with the events.

The exercise, coupled with U.S. casualties in Iran, shows American vulnerabilities to drones -- years after the U.S. made uncrewed systems an essential part of warfare. America pioneered using long-range drones in war. The Pentagon has recently spent billions acquiring new drone and counterdrone technology and formed special units to operate it.

Still, in the Middle East this year, the U.S. has struggled to defend against Iran's long-range drones, which have killed and injured soldiers and destroyed aircraft.

The drubbing in Germany conveyed lessons from Ukraine focused on short-range battlefield drones. The exercise, held in April and May, tested visiting troops' ability to operate and defend against the proliferation of smaller, front-line drones that have dominated the conflict between Russia and Ukraine.

Exercises like Combined Resolve are run precisely so that forces can experience realistic combat conditions. Army leaders in Europe over recent years have taken advantage of having Ukrainian forces on hand to participate and impart their hard-won skills to U.S. and allied troops in practice, on simulated battlefields. The expectation is that failures are educational. British and Swedish exercises have also resulted in easy Ukrainian triumphs.

Eliot Cohen, a scholar at the Center for Strategic and International Studies think tank, said that recent battlefield experience shows how drones of all kinds are essential to modern war.

"It is vital that the U.S. military master that, and thus far, unfortunately, that does not seem to be the case," he said.

Combined Resolve is a semiannual exercise focused on large-scale ground combat operations, in which rotating U.S. forces use armored divisions supported by ground troops, helicopters, drones and other military assets.

Around 3,500 U.S. personnel, primarily from the 3rd Armored Brigade Combat Team, 1st Cavalry Division, took part in the exercise. Their task was to attack a position defended by the Army training-ground's opposition force, or OPFOR, who were reinforced by Ukrainian troops from the 412th Regiment of Unmanned Systems Forces, or Nemesis, people familiar with the matter said.

The rotating troops were equipped with standard electronic-warfare and counterdrone systems, according to an Army official. New Mobile Brigade Combat Teams, equipped with the latest gear and tactics, have fared much better in exercises, the Army official said.

The Ukrainian drone operators eliminated a U.S. armored brigade in the exercise, according to U.S. officials briefed on the exercise and one participant.

The exercising troops sent into battle heavy armored vehicles that threw up dust, making them easy for Ukrainian reconnaissance drones to spot, according to the participant. Those drones were followed by drones dropping explosives and first-person-view drones, which smash into targets in combat, this person said.

Live ammunition is rarely used in such exercises. Drones typically hover above a vehicle or move close enough to it for an observer to award them a "kill."

Ukrainian drones were doing this so quickly with U.S. vehicles that they had to be sent back into the exercises as new units, or "re-spawned," to keep the exercise going, a U.S. official briefed on the drill said.

The U.S. reran the training scenario over the two-week engagement. The rotating forces improved their performance, as they became more adept at dispersing and concealing themselves and using electronic warfare, said the Army official. The Ukrainians also switched sides midway through the exercises and helped them use drone technology offensively, which they did effectively, the official said.

Ukrainian troops have become expert in drone warfare over nearly 4 1/2 years of fighting Russia, with operators and their support troops now skilled at continually repairing and adapting drones. Moscow's forces have also gained invaluable skills. American drone operators lack experience fixing and arming drones under fire, said the person present at the exercise.

In Ukraine, so many tanks and other armor are destroyed in battle that large parts of the country's vast front line is almost free of armor.

Some U.S. military officers, though, argue that drones are particularly deadly in this war because it has reached a stalemate with little battlefield movement. In a war of maneuver, the tank and other armor would come back into its own, they say.

But Ukrainian military thinkers such as former chief commander Valeriy Zaluzhniy argue that drone technology has made traditional maneuver warfare unfeasible, for now, explaining the largely static front line in Ukraine's east. Both Russia and Ukraine are searching for the next breakthroughs in technology and tactics to restore movement to the battlefield.

The exercise showed that the U.S. may struggle to protect that armor as it moves.

This wasn't the first time the U.S. has come across Ukrainian drone proficiency. In 2023, a U.S. infantry officer helping train Ukrainian troops realized the U.S. needed to learn from them about drone warfare and designed a training program that other Army units later followed, according to a U.S. official.

Despite a sometimes prickly relationship with Kyiv, President Trump's administration has been reaching out to Ukraine. The U.S. is currently testing Ukrainian drones to buy and has used counterdrone systems tested in that war to help defend its forces in Iran.

Defense Secretary Pete Hegseth in May told senators he has increased the number of U.S. personnel being sent to Ukraine to study drone warfare.

The U.S. Army isn't the first to be found wanting by Ukrainian drones.

In May of last year, Ukrainian drone operators easily defeated the British, Estonian and other forces from the North Atlantic Treaty Organization, including a U.S. contingent, in an exercise in the Baltic region, according to a person familiar with the matter.

This spring, Swedish forces led an exercise with NATO allies in which Ukrainian drone teams outperformed them too, Swedish officials told local media.

Write to Alistair MacDonald at Alistair.Macdonald@wsj.com, Lara Seligman at lara.seligman@wsj.com and Daniel Michaels at Dan.Michaels@wsj.com

(END) Dow Jones Newswires

August 12, 2026 13:19 ET (17:19 GMT)