NOVOMYKOLAIVKA, Ukraine—In this corner of southeast Ukraine, Russian forces are pummeling rear areas with drone attacks, seeking to sap the strength of Ukrainian defenders by cutting their supply lines. Snow-covered roads are littered with burned-out pickup trucks.
As the conflict nears the four-year mark, Russia’s increasingly effective use of drones is helping its forces maintain a grinding, slow-motion advance. It is weakening Ukraine’s hand at the negotiating table, where it is under pressure to cede strategically vital territory.
Russia’s battlefield drone strategy is focused on a medium range of about 12 to 50 miles. Priority targets include Ukrainian drone operators as well as logistics.
In contrast, Ukraine’s approach is still largely about inflicting maximum casualties on Russian infantry when they enter a kill zone beginning about 12 miles from the front line. Ukraine is betting on doing more of the same this year. The goal is to kill 50,000 Russian soldiers a month, up from 35,000 in December, new defense minister Mykhailo Fedorov said recently.
Many Ukrainian soldiers and officers say that a shift is needed and that Ukraine needs to match Russia’s strategy of systematically targeting the rear.
Ukrainian forces could better resist the relentless Russian pressure if they focused more on targeting Russian drone operators and company and battalion command posts many miles behind the line of contact, said Major Oleh Shyriayev, commander of the 225th Assault Regiment, which is fighting off constant Russian assaults in the southern Zaporizhzhia region.
“Everything rests on their shoulders at the tactical level,” he said.
Russian soldiers killed and wounded have reached nearly 1.2 million, according to the Center for Strategic and International Studies in Washington. But even that toll hasn’t led the Kremlin to relent. Ukraine’s military has likely suffered between 500,000 and 600,000 total casualties, CSIS estimates.
“Russia has adopted a much more systematic approach of hunting for Ukrainian drone teams, to disrupt and destroy Ukrainian drone logistics, because that’s the center of gravity of the Ukrainian defensive system,” said Franz-Stefan Gady, a Vienna-based military analyst. Ukraine has better individual drone pilots, but their strikes against targets in the rear are more piecemeal, he said.
Ukraine is short of drones and other weapons that can hit midrange targets at 20 to 120 miles behind the front line, Gady noted. More help from Western partners would be needed to improve its arsenal.
Here in the Zaporizhzhia region, it is easy to see why Russia’s army still can’t achieve a decisive breakthrough, despite having more men and munitions.
The snowy plains stretch for miles, occasionally interrupted by bare trees. The sky buzzes with deadly Ukrainian drones when Russian infantry try to cross the fields. Long ditches lined with coils of razor wire and concrete pyramids known as dragon’s teeth await Russia’s increasingly rare armored attacks.
The bare terrain doesn’t defend itself, however. Shyriayev’s troops are working like firefighters, rushing to respond when Russian soldiers find gaps in the thinly held front line. They are doing their best to make the strategy work, said Shyriayev.
Ukraine has more troops holding the line in the eastern Donetsk region, the war’s single biggest battlefield. That has left it short of troops to cover the southern front.
Russian forces are now barely 14 miles from the outskirts of Zaporizhzhia city, putting it within range of some of their drones. Fears are growing in the city, whose prewar population was 700,000, that Russia could seek to make daily life impossible with constant drone attacks on civilians, like it has done in the city of Kherson.
In the countryside some 15 miles behind the southern front, Ukrainian troops’ challenges are apparent. Antidrone nets cover long sections of road. In some sections, workers struggle to repair sections of netting torn by sleet and ice.
The Russians pick a road and try to destroy everything on or near it, said a deputy brigade commander on the southern front. Their goal is to break Ukrainian soldiers mentally by making all movement to and from the line of contact terrifying, he said.
His brigade is building up its midrange drone capabilities to hit Russian forces at up to 15 miles behind the front line, before they can launch infiltration attempts, he said. But more progress is needed.
The Russians rarely assault Ukrainian positions directly these days. Instead, small numbers of soldiers try to bypass them and get as far into the rear as possible to sow chaos. The Russians pay a high price, but they keep coming.
Near the town of Hulyaipole, which the Russians have partly taken, a Ukrainian surveillance-drone pilot known by his call sign Kuts was flying his drone back to base to recharge its battery recently. On the drone’s video feed, he spotted three Russian soldiers only a kilometer away. “No one can understand how they got there,” he said.
He directed attack drones to the spot, which killed the Russians.
For Ukrainian infantrymen, Russia’s midrange drones make moving to and from the front line the most perilous part of their work.
“During rotations, unfortunately, there are a lot of losses, the most losses,” said a 52-year-old rifleman known by his call sign Psycho. His face bore the extreme exhaustion typical of men who have spent too long in front-line dugouts. After a few days’ rest at his brigade’s psychological support center, he returned to the front.
Kuts, the drone pilot, said he was paying only limited attention to the peace negotiations with Russia, the U.S. and Ukraine. With no deal in sight, it is more useful to watch the icy fields of Zaporizhzhia on his video feed, he said.
“They say one thing publicly,” he said. But on the battlefield, “I see intensified assault operations.”
Write to Anastasiia Malenko at anastasiia.malenko@wsj.com and Marcus Walker at Marcus.Walker@wsj.com