Gradually, Then Suddenly: A Russian Breakthrough Near Pokrovsk Sets Ukrainian Alarm Bells Ringing

It's one of Russia's biggest battlefield advances in months. For Ukraine, it couldn't come at a worse time.

Sometime over the weekend, Russian troops broke through Ukraine defensive lines north of the Donbas city of Pokrovsk, east of the smaller town of Dobropillya. According to military analysts and Ukrainian and Russian open-source bloggers, Russian units have pushed some 17 kilometers north of their previous lines -- a huge leap by recent battlefield measures -- capturing the village of Zolotiy Kolodyaz and coming close to a secondary supply road that stretches from Dobropillya to the north.

Some open-source reports suggest Russian forces may have actually captured the road and the village of which would further threaten supply lines for Pokrovsk, which itself is partially encircled. Last week, Russian sabotage units were reportedly spotted in the city's southern outskirts, pushing toward the city's train station in the center.

Ukraine Suffers Losses Near Pokrovsk As Russia 'Throws Cannon Fodder' Into Combat

In a post to Telegram on August 12, Ukraine's top military commander, General Oleksandr Syrskiy, confirmed "infiltration" units had bypassed some Ukrainian positions: "Some of the groups have already been destroyed, the rest are in the process of being destroyed."

Reinforcements from some of more battle-hardened units are also now being deployed.

Ukrainian officials have stepped up their efforts to evacuate residents of Pokrovsk, which is increasingly threatened by Russian advances.

Coming on the eve of a major face-to-face meeting of US President Donald and Russian President Vladimir Putin set for August 15 in Alaska, where Trump has suggested a deal could be reached involving "land swap," the recent battlefield losses are worrying, if not alarming, experts said.

"If the Ukrainians don't restore the situation quickly and the Russians are able to consolidate and expand this into a proper breakthrough, then it could be one of the more significant events of this war," said Pasi Paroinen, a Finnish reserve officer and military analyst with the open-source intelligence organization Black Bird Group. "A lot depends on how the Ukrainians are able to respond."

"The fall of Pokrovsk is just a matter of time at this stage," said Konrad Muzyka, a Polish-based military analyst who recently returned from touring parts of Ukraine's forward positions.

"Ukrainians don't have the manpower to fight in the city, the capacity to conduct a flanking maneuver to cut Russians off from southern parts of the town," he said in an interview. "We are now probably just seeing a sort of delaying action and an effort to bleed the Russians as much as possible…rather than an attempt to retake the city."

A Ukrainian military spokesman explicitly denied reports of a Russian breakthrough.

"The Russians are using the tactic of infiltration by small groups past the first line of defense, losing a lot of personnel, which happened near Dobropillya," Lieutenant Colonel Viktor Tregubov said in a video posted to Facebook on August 12. "A small enemy group bypassed Ukrainian positions and tried to hide to our rear, but [our armed forces] are repelling such attempts."

'We Keep Killing Them, And They Keep Sending Them'

Since last winter, the 1,100-kilometer front line has shifted at only an incremental pace, despite Russia having vastly more troops and more weaponry.

Ukraine's ability to innovate on the battlefield -- particularly with drone warfare -- had given Kyiv a slight edge over Russian forces, which had long relied on Iranian-built kamikaze drones.

But Russia has matched many of Ukraine's innovations, particularly with electronic signal jamming -- which muddles Ukrainian drone fights -- and with fiber-optics drones -- where the devices are controlled by filament threads that spool out for kilometers, rendering them safe from jamming.

Moscow has also relied on glide bombs -- retrofitted heavy explosive "dumb" bombs that can be dropped by jets far from anti-aircraft defenses -- to devastate Ukrainian trenches or makeshift positions hidden in apartment building rubble.

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One of the bloodier tactics Russia has employed to break through Ukrainian lines has been mounted motorcycle or motor-buggy units, where a small number of lightly armed soldiers speed across the battlefield, trying to evade drones and maneuver behind Ukrainian positions.

Though they result in high casualty rates, the motorized assaults have been effective, in part because there aren't enough Ukrainian soldiers to adequately occupy trenches or foxholes.

"We keep killing them, and they keep sending them," one officer from Ukraine's 36th Separate Marine Brigade, told RFE/RL's Ukrainian Service. In line with military protocol, he gave only his call sign, Tikhy. "If they find a place [where they can get through], they immediately send them there. It's like the tactics ants use. They know there's sugar there, and they all start heading there."

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Ukraine, meanwhile, continues to struggle with recruiting and training enough soldiers to deploy, particularly infantry to deploy to frontline trenches. Lawmakers overhauled mobilization regulations last year, but experts say recruiters still struggle both to attract volunteers but also train them properly.

One newly formed French-trained and armed brigade saw scores of desertions before and after deploying, prompting a criminal investigation and the resignation of its commander.

The breakthrough near Doborpillya may have occurred after Russian saboteur and reconnaissance units infiltrated behind Ukrainian positions -- not unlike what appears to be happening in parts of Pokrovsk.

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If the Russians hold their positions and the road, that potentially opens a wedge in Ukrainian lines, allowing Russians to press south toward Pokrovsk and north toward Kramatorsk.

"It's the result of the lack of manpower," Muzyka said. "The forward line of Ukrainian troops is incredibly porous. Simply they do not have the men to man the fortifications that they built, the trenches that that they have."

For Ukraine, "the biggest shortcoming is manpower, which is essentially seen across the entire front," he said. "I don't think that the issue linked to mobilization is going to be solved, because it's just a fundamental structural issue of how Ukraine fights the war."

Agglomeration Threatened

One of Russia's main priorities in the Donbas region, experts and strategists said, appears to be two of Ukraine's current strongholds: Slovyansk and Kramatorsk.

Situated in the northern part of the Donetsk region, the twin industrial cities -- often lumped together as an "agglomeration" -- house a substantial grouping of Ukrainian forces as well as rear-guard supply lines, medical facilities, and local command headquarters.

Russian troops claim to have taken Chasiv Yar, a height-of-land city whose relative elevation provides an artillery vantage point to threaten Kostyantynivka , home to an important railway junction. Ukraine says the city is still contested.

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The agglomeration "is much more important for the enemy. This is actually the center of the Donbas, so it is logical that they were going to assault there," Kirill Sazonov, an analyst serving with Ukraine's 41st Separate Mechanized Brigade, told RFE/RL's Ukrainian Service. "But now they have decided to finish off Pokrovsk first, because, as the last six months have shown, it is impossible to storm Pokrovsk and Kostyantynivka simultaneously."

Around the beginning of the year, Russia set up a dedicated drone unit called the Rubicon Center of Advanced Unmanned Systems, an elite unit that uses advanced first-person-view drones -- drones piloted by operators who guide them using forward-looking video -- and test new tactics and technologies.

Experts say Rubicon played a pivotal role in driving Ukrainian troops out of Kursk, the Russian region Ukraine invaded last summer.

"What really surprised me was how Russians improved, how they were employing their drones," Muzyka told RFE/RL. "Rubicon is wreaking havoc on the Ukrainian second lines and the third lines [of defense] and they are just doing it in a very systematic, very methodical way."