Russia appears to infiltrate first ‘fortress city’ as Ukraine changes guard

xwhatsapp-strokecopylinkgoogleAdd Al Jazeera on GoogleinfoIn this photo provided by the Ukrainian State Emergency Service, rescuers search through the rubble at a private house following a Russian air attack in the Dnipropetrovsk region, Ukraine, on Thursday, July 30, 2026 [Ukrainian State Emergency Service via AP]By John T PsaropoulosPublished On 31 Jul 202631 Jul 2026Russia claimed this week to be advancing into Ukraine’s regions of Sumy, Kharkiv and Donetsk, as Ukraine installed new political leadership in its defence ministry and a new military leadership in its armed forces.

The changes followed the unprecedented firing of both defence minister Mykhailo Fedorov and commander-in-chief Oleksandr Syrskii within a week.

Most concerning was the news from Ukrainian soldiers in the eastern region of Donetsk that Russia was “effectively cutting off” Kostiantynivka, the southernmost of four “fortress cities” Russia had pledged to overthrow in a bid to capture the remaining free territory of the region by the end of the year.

Kostiantynivka was “the key to liberating the entire territory of the Donetsk People’s Republic”, Russian President Vladimir Putin recently said.

“Things are very bad in Kostiantynivka. It’s not a question of whether we’ll lose [it] or not – we’ve effectively already lost it,” a soldier told the Ukrainian news outlet Hromadske. “If there’s a large number of Russians there, you can’t really say we’re holding it. They’re just pushing our guys into a corner.”

A local Ukrainian commander told Hromadske that Russians were moving into the villages of Molocharka and Izhevka north of the city, and his units could find themselves surrounded in “another month or two” unless reinforcements arrived or containment tactics changed.

Shortly before he was dismissed on July 21, Syrskii had painted a more optimistic picture, saying there were an estimated 145 Russian infiltrators in the city who were suffering “significant losses” of about 25 people a day, as Ukrainian drone units hunted them down in their urban shelters.

The commander of a group called Kurt and Company shared that more optimistic view with the news outlet Suspilne.

“Heavy fighting and gunfire are going on all over the city,” said the commander, identified by the call sign Kurt. “But we still control most of the city and the enemy is mainly on the flanks. They are trying to bypass us, cut us off, but we are holding our defence there. We are just constantly under attack from the KABs – they are just taking out positions with aerial bombs. This is the only thing that still gives the Russians success and this is a big problem for us.”

KABs are massive aerial ordnance with payloads of between 500kg and 3,000kg, which Russia has been dropping on Ukrainian positions at a rate of more than 200 and sometimes more than 300 a day. Ukraine has repeatedly placed aerial defence equipment at the top of its list of requirements from allies.

As recently as three weeks ago, the Institute for the Study of War, a Washington-based think tank, estimated that Russian forces had a presence in just 37 percent of Kostiantynivka, mostly in the form of “infiltrations” rather than firm control. Its most recent assessment of Russian infiltration suggests that it has spread to most of the city, however.

Overall, Russian forces have been slowing down, though. The ISW estimated that they were capturing 16.6sq km a day in the first half of 2025, but just 1km a day in June this year. In July, the ISW has assessed that Russia has been losing territory at a rate of 1.6sq km a day.

Now, it appears that Russia has been mounting an effort to regain the offensive. The commander of Ukraine’s Unmanned Systems Forces (SBS), Robert Brovdi, said “the actual number of enemy personnel involved in offensive operations along the front line” during the month had increased by 12 percent compared with June and 18 percent compared with May, based on analysis from the SBS intelligence centre. Russian casualties increased by similar proportions, he said.

In the northern Kharkiv and Sumy regions, Russia claimed to have destroyed 10 Ukrainian unmanned aerial vehicle (UAV) control centres on July 27, killing 70 personnel.

Three days later, it said its troops had routed defenders in Nova Sich, Mogritsa and Malaya Slobodka in Sumy and Yurchenkovo in Kharkiv, by copying the Ukrainian tactic of using drones to disrupt ammunition deliveries.

“Russian servicemen found large amounts of abandoned weapons, ammunition and military equipment,” according to a Russian report.

A local Russian official claimed Moscow had captured 13 settlements in Kharkiv this month.

Al Jazeera could not independently verify the Russian claims, which have in the past been inflated or premature, and Ukraine denied Nova Sich had fallen.

Ukrainian President Volodymyr Zelenskyy said this week he had received intelligence that Russia was preparing an “expanded mobilisation” to counter losses of 225,000 this year, versus recruitment of 221,000 people. Six out of 10 casualties were fatalities, he said.

Zelenskyy told Sky News Putin aimed to raise 300,000 to 500,000 troops in early October, after Russian parliamentary elections had taken place in September. “He will not be able to quickly prepare these people. This, again, means that he will send poorly trained people to the battlefield, which will inevitably lead to heavy losses,” Zelenskyy said.

More worrying, perhaps, were the 30,000 North Korean troops Russia was preparing barracks for in Voronezh, in southwestern Russia, according to Zelenskyy. Russia received 3,000 North Korean soldiers in 2024, and used them to reclaim territory Ukraine had counterinvaded in Kursk.

Fedorov announced a plan in June to attract foreign fighters by raising the salary for a front-line soldier to $7,000 a month. “I believe that 50 percent of the front line or among the attack aircraft could be foreigners,” he told Ukrainska Pravda this week.

Russia estimates that Ukraine currently employs about 4,000 foreign troops. Ukraine’s armed forces are estimated at 900,000 people.

Ukraine struck blows in its economic war against Russia, hitting refineries and oil depots.

Those included confirmed hits against the Subkhankulovo oil tank farm in Bashkortostan, 1,350km from Ukraine, six refineries, an oil loading terminal at Rostov-on-Don, and fuel and lubricant depots at Ishki in occupied Crimea and Udmurtia.

Ukraine has recently struck targets as far afield as 2,500km, and Zelenskyy said it had now acquired range of at least 3,000km.

Ukraine claims to have disabled 42 percent of Russian refining capacity this year. A Financial Times investigation using satellite photographs confirmed that it had disabled 45 percent of nominal capacity and 30 percent of actual capacity, causing damage lasting weeks or months.

Russia, which has been experiencing a fuel crisis as a result, extended a fuel export ban from the end of August to the end of January.

Ukraine also struck military production targets, including the Avitek plant in Kirov city, producing components for aviation and missiles, and an S-400 radar. On July 27, it downed a Forpost-R heavy drone used to carry KABs – only the sixth such prize of the entire war.

Brovdi’s forces continued to starve Crimea of electricity and fuel, striking 37 electricity substations and four oil tankers during the week, bringing the total number of electricity infrastructure nodes struck in July to 164, and the total number of tankers hit in the Black and Azov seas to 205.

Brovdi’s forces focused much of their fire on the warehouses of the Wildberries online retailer, suspected by Ukraine of providing equipment to mobilising troops.

During the past week they have struck warehouses in Voronezh, Leningrad, Simferopol, Udmurtia and Penza, bringing the total number of warehouses set ablaze to 12 and the estimated damage to $2.2bn.

Russia also claims to have hit military targets in massive drone and missile attacks on Ukraine, but many of the hits were civilian.

One person died when a supermarket in Chernihiv, northern Ukraine, was struck on July 26, and the entire Voronov family was wiped out in Radushne in central Ukraine when their house was blown to smithereens on July 30. A record 56,000 people spent the night sheltering in the Kyiv Metro that night.