NATO commanders are warning that the alliance must rapidly adapt to a new era of warfare dominated by artificial intelligence-powered drones or risk falling behind Russia on the battlefield, The Telegraph reported on Monday.

The concerns were underscored during Northern Star, a major NATO exercise involving some 5,000 troops from seven nations in Finland's heavily forested eastern region, where simulated battles highlighted the growing vulnerability of traditional armored forces.

In one exercise scenario, anti-tank teams ambushed a column of Finnish Leopard 2 tanks hidden among dense woodland just 18 miles from the Russian border. In another, drones and artillery strikes immobilized armored vehicles that had clustered too closely together.

While the attacks were simulated, military leaders said they reflected battlefield realities that have emerged during Russia's war in Ukraine.

"NATO commanders now face a looming crisis: learning how to fight on a 21st-century battlefield dominated by AI-assisted drones," military officials involved in the exercise said.

The warning comes amid growing concern that Russia has gained valuable experience in drone warfare through more than four years of combat in Ukraine. Latvia's military leadership recently cautioned that Moscow could exploit gaps in Europe's military readiness and potentially threaten the Baltic states before the end of the decade.

The war in Ukraine has reshaped military planning across the alliance. According to Ukrainian military estimates, Russia has lost nearly 12,000 tanks and 25,000 armored vehicles since the invasion began, while Ukrainian forces have also suffered thousands of losses.

Military officials say drones now account for more than 90% of battlefield casualties, with armored vehicles among their primary targets.

Finnish tank commander Cpl. Julius Arkkilä, whose crew was "eliminated" during one of the Northern Star training scenarios, said drones have fundamentally altered battlefield conditions.

"Operating a tank in this terrain is dangerous, because there are drones now, so you need to keep your eyes on the air and then on the road and everyone else," Arkkilä said. "Things can change in a second."

The exercise was conducted against the backdrop of increasing concern over Russia's military activity near Finland's 830-mile border, NATO's longest frontier with Russia. Finnish intelligence officials have warned that Moscow is rebuilding military infrastructure and expanding troop deployments in the region, despite continuing losses in Ukraine.

Maj. Gen. Pekka Turunen, Finland's defense intelligence chief, said Russia is accelerating its military buildup along the border and could shift future force development toward the Finnish frontier once the conflict in Ukraine ends.

The challenge for NATO extends beyond defending its eastern flank. Military planners increasingly believe the alliance must speed up procurement of drones, autonomous systems and counter-drone technologies while integrating artificial intelligence into battlefield operations.

Gen. Christopher Donahue, commander of U.S. Army Europe and Africa, said NATO "has changed our exercises to directly rehearse how we will fight," referring to NATO's Eastern Flank Deterrence Initiative, which stretches from Finland to Romania.

Military officials acknowledged that NATO's drone inventories could be depleted quickly in a major conflict with Russia, underscoring the need to expand production capacity and stockpiles.

The Northern Star exercise also marked the first large-scale NATO training event in Finland since the Nordic nation joined the alliance in 2023 following Russia's invasion of Ukraine.

As NATO races to modernize, military leaders say the lessons from Ukraine are clear: Future wars are likely to be decided not only by tanks and artillery but also by the side that can best integrate drones, artificial intelligence and autonomous systems into combat operations.