Russia reportedly penetrates much of 'fortress city' Kostiantynivka as Ukraine changes command

Russia claimed this week to be advancing into Ukraine's Sumy, Kharkiv, and Donetsk regions, while Kyiv appointed new political leadership for the Defense Ministry and new military leadership for the armed forces.

The changes came after both Defense Minister Mykhailo Fedorov and Commander-in-Chief Oleksandr Syrskii were dismissed within a week, an unprecedented move.

Most concerning are reports from Ukrainian soldiers in the eastern Donetsk region that Russia is "almost cutting off" Kostiantynivka, the southernmost of four "fortress cities" Moscow has vowed to capture to secure the rest of the region by year-end.

Russian President Vladimir Putin has called Kostiantynivka the "key to liberating the entire territory of the Donetsk People's Republic."

"The situation in Kostiantynivka is very bad. It's no longer a question of whether we lose it – in fact, we've already lost it," a soldier told Ukrainian outlet Hromadske. "If there are large numbers of Russians there, you can't say we're in control. They're just pushing our people to the wall."

A local Ukrainian commander said Russian forces were advancing into the villages of Molocharka and Izhevka north of the city, and his units could be surrounded within "a month or two" without reinforcements or a tactical change to stop them.

Just before his dismissal on July 21, Syrskii painted a more optimistic picture, saying some 145 Russian soldiers had infiltrated the city and were suffering "significant losses" of about 25 per day as Ukrainian drone units hunted them in urban shelters.

The commander of a group called Kurt and Company also shared a more upbeat view with Suspilne. "Heavy fighting and gunfire are happening throughout the city," commander Kurt said. "But we still control most of the city and the enemy is mostly on the flanks. They're trying to go around, cut us off, but we're holding the line there. We're just constantly being hit by KABs – they're destroying positions with aerial bombs. That's the only thing giving the Russians success, and it's a big problem for us."

KABs are large aerial bombs with warheads weighing from 500kg to 3,000kg, which Russia has dropped on Ukrainian positions at a rate of more than 200, sometimes over 300, per day. Ukraine has repeatedly placed air defense equipment at the top of its request list from allies.

Just three weeks ago, the Washington-based Institute for the Study of War (ISW) estimated Russian forces were present in only 37% of Kostiantynivka, mostly as "infiltration" rather than firm control. However, the institute's latest assessment of Russian penetration suggests it has spread to most of the city.

Overall, Russia's advance has slowed. ISW estimates they took 16.6 square kilometers per day in the first half of 2025, but only 1 square kilometer per day in June this year. In July, ISW assessed Russia lost territory at a rate of 1.6 square kilometers per day.

Now, Russia appears to be trying to regain the offensive initiative. Ukrainian Unmanned Systems Forces (SBS) commander Robert Brovdi said "the number of enemy personnel involved in offensive operations along the front line" this month rose 12% from June and 18% from May, based on analysis from the SBS intelligence center. Russian losses also increased at a similar rate, he said.

In the northern Kharkiv and Sumy regions, Russia claimed to have destroyed 10 Ukrainian drone control centers on July 27, killing 70 personnel.

Three days later, Russia said its troops had defeated defenses at Nova Sich, Mogritsa, and Malaya Slobodka in Sumy and Yurchenkovo in Kharkiv, by copying Ukraine's tactics of using drones to disrupt ammunition supplies.

"Russian servicemen found a large amount of weapons, ammunition, and military equipment left behind," 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 Russian claims, which have previously often been exaggerated or premature, and Ukraine has denied the fall of Nova Sich.

Autumn offensive?

Ukrainian President Volodymyr Zelenskyy said this week he had intelligence that Russia is preparing a "large-scale mobilization" to compensate for losses of 225,000 people this year, while recruitment has only reached 221,000. Six out of ten casualties are deaths, he said.

Zelenskyy told Sky News that Putin aims to mobilize between 300,000 and 500,000 troops by early October, after Russia's parliamentary elections in September. "He won't be able to prepare these people quickly. This again means he will send poorly trained people to the battlefield, which will certainly lead to heavy losses," Zelenskyy said.

Perhaps more concerning is Russia preparing barracks for 30,000 North Korean troops in Voronezh, southwestern Russia, according to Zelenskyy. Russia took in 3,000 North Korean soldiers in 2024 and used them to regain territory Ukraine had captured in its counteroffensive in Kursk.

Fedorov unveiled plans in June to attract foreign soldiers by raising frontline pay to $7,000 per month. "I believe 50% of the frontline or strike aircraft could be foreigners," he told Ukrainska Pravda this week.

Russia estimates Ukraine currently uses about 4,000 foreign troops. Ukraine's armed forces are estimated at around 900,000 personnel.

Long-range strikes

Ukraine has hit Russia in the economic war, targeting oil refineries and depots.

Among them are confirmed strikes on the Subkhankulovo oil depot in Bashkortostan, 1,350km from Ukraine, six oil refineries, an oil loading terminal at Rostov-on-Don, and fuel and lubricant depots at Ishki in occupied Crimea and Udmurtia.

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

Ukraine claims to have knocked out 42% of Russia's refining capacity this year. A Financial Times investigation using satellite imagery confirmed it has disabled 45% of nominal capacity and 30% of actual capacity, causing damage lasting weeks or months.

Russia, which is experiencing a fuel crisis as a result, has extended its fuel export ban from late August to late January.

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

Brovdi's forces continue to squeeze Crimea on electricity and fuel, striking 37 substations and four oil tankers in a week, raising the total number of power infrastructure points hit in July to 164 and total oil tankers struck in the Black and Azov Seas to 205.

Brovdi's forces have focused much fire on warehouses of online retailer Wildberries, which Ukraine suspects supplies equipment to the mobilized military. In the past week, they hit warehouses in Voronezh, Leningrad, Simferopol, Udmurtia, and Penza, bringing the total burned to 12 and estimated damage to $2.2 billion.

Russia also claims to have hit military targets in major drone and missile attacks on Ukraine, but many strikes have hit civilians.

One person was killed when a supermarket in Chernihiv, northern Ukraine, was hit on July 26, and the entire Voronov family was killed in Radushne, central Ukraine, when their house was blown up on July 30. A record 56,000 people spent the night sheltering in Kyiv's metro that night.