Soldiers from Ukraine’s 128th Mountain Assault Brigade say they have been forced to operate underground due to the growing threat posed by Russian drones. In a report published by The Economist, Ukrainian servicemen described how relentless aerial surveillance and strikes have made frontline operations increasingly hazardous.

The brigade’s commander, speaking to the publication, explained that until January, his unit had been stationed closer to the front. However, as Russian drone strike zones expanded, the decision was made to relocate personnel to safer, rearward positions. He said troops are now based below ground, and construction of a specialized bunker is expected to be completed by mid-August.

According to The Economist, short-range drones currently strike targets up to 15 kilometers on both sides of the front line. Their frequent deployment has made troop movements and combat operations extremely risky.

The report also warned that the continued rise in medium-range drone usage could significantly broaden the threat zone. Within the next year, the strike radius may reach 60 kilometers or more-endangering Ukrainian logistics, artillery positions, and troop deployments deep behind the front.