MALA TOKMACHKA, Ukraine — Just half a mile from the enemy's deeply fortified trench, a reconnaissance team hunted the Russian positions by drone last week, live-streaming video for Ukrainian gun crews and their commanders.

U.S.-provided M777 howitzers boomed far behind them. Shells whistled overhead, and the spotters watched them hit Russian positions on the ridge through the video screens of their controllers. The blast wave rolled in a moment later, as smoke boiled up. Then more artillery fired, this time at the enemy flank, in a coordinated effort to take back Russian-occupied territory, one bite at a time.

The unit of mostly young soldiers with the 78th Regiment had been flying drones since sunup on this area of the southern front, key players in the painstakingly slow counteroffensive that has become an artillery duel guided by drones.

"Once I came here I was really upset," said Labrador, speaking on the condition he be identified by his call sign, in accordance with Ukrainian military protocol. "We all were thinking it could be really easier, especially here."

Labrador, a self-described "newbie" to combat, had hoped that in this area — unlike in Luhansk and Donetsk, where both sides have been fighting for more than eight years — Ukraine might punch through Russian-occupied territory and cut off Moscow's lifeline to Crimea, thanks to Leopards, Bradley fighting vehicles and other sophisticated weapons donated by Western allies.

But here, too, Ukrainians have encountered a deeply entrenched enemy.

For months, Russian forces have been digging, building concrete bunkers and constructing tunnel networks like "underground cities" to thwart Ukrainian attacks, Labrador said. Russian fighter jets and helicopters also conduct frequent missions, lifting off from airfields only minutes away in Crimea. Much of Ukraine's vast farmland, gone to seed with wildflowers instead of crops, has been sown with deadly mines.

"It's a huge system of defense," he said.

So Labrador has stopped trying to predict when Ukraine's armed forces might reach Melitopol or Mariupol — or even Tokmak up ahead, another key objective on their drive south to the Black Sea coast and Sea of Azov.

"I just focus on my work to make as much effort as I can," Labrador said, as a Soviet-era automatic grenade launcher let off a rapid-fire burst across the way.

As Ukraine marked its 500th day of war, President Volodymyr Zelensky and other leaders, in videos and communiqués posted on Telegram, wanted to send the message that its long-awaited counteroffensive was moving forward, however slowly.

On the southeastern front, about 46 miles southeast of Zaporizhzhia, Ukrainian forces have struggled to enlarge the pocket that has opened between Mariupol and Melitopol since the counteroffensive began more than a month ago. An initial thrust by an armored column near Orikhiv suffered significant losses, including German-made Leopard tanks.

Hanna Maliar, Ukraine's deputy defense minister, said in a post on Telegram that, while Ukrainian forces continued to advance south of Bakhmut in a bid to retake the city, the southern front — despite intense fighting in places — has settled into an artillery battle while other units remove mines and probe for openings.

The pro-Russian military blog Rybar, posting on Telegram, offered a similar assessment of the counteroffensive, though he called the Zaporizhzhian sector "the hottest," with heavy fighting northeast of Robotyne.

Konrad Muzyka, a military analyst with Rochan Consulting in Poland, said it shouldn't be a surprise that Moscow invested heavily in defending Russian-occupied approaches to the land bridge now connecting its mainland to the Crimean Peninsula, which Russia seized and illegally annexed in 2014.

"So Ukrainians knew it, and Russians knew it as well," Muzyka said in an interview. "The big prize in this war is the land corridor between Russia and Crimea."

Though some analysts characterized last month's push with Leopard tanks near here as a probing action, Muzyka said it looked more like an important attempt at a breakthrough that failed. And now both sides have settled again into a war of attrition almost everywhere, except near Bakhmut.

"Russian defensive operations have been very well conducted, apart from the initial gains that Ukraine made in the first couple of days of the main phase of the offensive," Muzyka said.

Muzyka said he expected Ukraine to shift units toward Bakhmut's southern flank to build on momentum there, while keeping sufficient forces on the southern fronts to tie up the Russians, including along the Zaporizhzhian axis.

After days of fierce fighting that included Russian airstrikes and guided-missile attacks, Ukrainian troops advanced beyond the ruins of Orikhiv, whose prewar population numbered about 14,000. And they have pushed past Velyka Novosilka, Vuhledar and this village, another ghost town with no sign of the 3,000 people who once lived here.

Days ago, with the moon nearly full against a patchy sky, the team of spotters loaded their gear into a camouflaged pickup about 3 a.m. and sped through Orikhiv and other heavily damaged settlements.

Their front-line position, steps away from a Ukrainian mortar crew that had been shelling all night, looked across a field strewn with purple and yellow wildflowers. Beyond the field was a low ridge held by Russian forces.

The team was smoking cigarettes and joking around, almost more concerned that they had left the day's food supplies in the pickup because another delivery within range of Russian artillery would be dangerous. Several moved around the trench without helmets, or even body armor, despite its proximity to Russian fire.

"So we will be up in the air in 10 minutes," said Vidmak, speaking in English and identifying himself by his call sign - which means "Witcher," a name taken from a Netflix series in which the lead character also ties his hair into a ponytail.

The team, using spotter drones and kamikaze drones rigged with explosives, had lost one the day before while trying to destroy a Soviet-made antitank weapon. Perhaps the drone had strayed off course because of signal jamming or while flying near the limit of its range — something not uncommon since the Russians, holding the high ground, forced the drones up another 650 feet or more.

Once aloft, the team's drone pooled its live video with video from other teams, which could be viewed on a digital tablet with the touch of a finger. Commanders and pilots conferred on Google Meet about where and when to strike.

"Calling Kurgan," Vidmak says, speaking to another pilot.

"Kurgan is listening."

"Are you taking off?"

"We're halfway there."

"Plus," Vidmak says, their way of acknowledging the message.

Within minutes, his team had their drone aloft, too, allowing them to watch the artillery battle unfold in front of him in real time on his video screen and whenever he raised his eyes toward the smoking ridge across the field.

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