Ukraine has completed its Operation Vivaldi, aimed at protecting its fortress belt cities of Donetsk Oblast, which helped Kyiv preserve the region from Russian occupation for 12 years. Brigadier General Andrii Biletskyi, the commander of the Third Army Corps behind the operation, has reported that the fourth phase secured 101 km² of territory. Among the latest achievements is the liberation of three settlements—Zelena Dolyna, Lypove, and Kolodiazi.

The operation's main objective was to move Ukrainian troops into more advantageous defensive positions, Biletskyi said in the first days after the operation was made public. Vivaldi has now summed up the results of all four phases: Ukraine has established full control over 16 settlements, liberated 277 km² of territory, and inflicted 8,000 casualties on Russian forces.

Ukraine worked against Russia's deadline

During Operation Vivaldi, Ukrainian forces have prevented Russian troops from outflanking the Sloviansk-Kramatorsk agglomeration and cutting the Kharkiv–Sloviansk highway, a key supply route for Ukraine’s forces in Donbas, Biletskyi says.

“We thwarted the offensive of the Zapad grouping and forced it to redeploy some units of the 1st Tank Army, which eased pressure on Kupiansk-Vuzlovyi,” Biletskyi announces.

Previously, the Institute for the Study of War noted that Russian President Vladimir Putin was confident that Russian forces would be able to seize the entire Donetsk Oblast by the end of 2026 — the Kremlin’s latest deadline for achieving this goal.

Ukraine’s military was on a mission to prevent this.

Season one: clearing russian infiltration groups

On 15 September 2026, Ukraine’s Third Army Corps announced Operation Vivaldi in northern Donetsk Oblast. During the first phase, Ukrainian troops cleared Russian groups from 75 km² of territory and liberated another 10 km².

The Third Army Corps said it had struck Russian supply routes and fuel infrastructure, prompting Russia to relocate its fuel and lubricant reserves to Voronezh Oblast. According to the corps, Russian forces lost around 1,500 troops, more than 12,000 drones, and hundreds of pieces of equipment.

Season two: liberation of Shandryholove and Derylove

On 20 September, the Third Army Corps reported the liberation of Shandryholove and Derylove and the establishment of full control over Drobysheve.

During the second season, Russian forces lost another 800 troops, bringing their total losses across the first two seasons to more than 3,000, according to the corps.

During the first two seasons of the operation, Ukrainian troops and attached units regained control of 125 km² of territory, including 50 km² that had been fully liberated.

The first phase of Vivaldi involved eliminating Russian groups that had infiltrated Ukrainian positions, explained the commander of a battalion in the 125th Brigade, callsign Darwin, per ArmyInform. After clearing those groups, the Defense Forces moved on to the operation’s second phase, using reconnaissance drones to detect Russian forces, he added.

For this, Ukraine used UAVs and ground robotic systems.

“The Third Army Corps was the first in the world to begin deploying ground robotic systems by air. Our heavy bombers deliver kamikaze ground robotic systems more than 10 kilometers behind enemy lines,” Biletskyi noted.

Season three: advances near Novе and Ridkodub

On 28 September, the Third Army Corps reported the liberation of Nove, Ridkodub, and Katerynivka and the restoration of control over Karpivka and Novomykhailivka. Ukrainian forces regained another 51 km² of territory, bringing the total area liberated since the start of the offensive to 176 km². Russian forces lost around 2,000 troops, and more than 250 were taken prisoner, the corps said in its summary of the operation’s third phase.

“The Russians were convinced that the main axis of attack was Shandryholove–Zelena Dolyna. This led it to squander its reserves in counterattacks along that very axis. The Russians slept through the actual strike, which was focused on capturing Nove,” Biletskyi said.

Operation Vivaldi aimed to disrupt Russia’s plans in Donetsk Oblast

The need for Operation Vivaldi arose amid Russian attempts to encircle Ukraine’s fortified belt in Donetsk Oblast. Ukrainian forces conducted preparatory efforts aimed at degrading Russia’s offensive capabilities, including strikes on Russian drone operators, the Institute for the Study of War reported on 9 October.

Ukrainian counterattacks in the Lyman direction and east of Sloviansk and Kramatorsk were intended to complicate Russian efforts to seize the fortified belt in Donetsk Oblast, the report noted.

The corps advanced gradually, reclaiming small areas instead of attempting a large-scale breakthrough.

Ukrainian marines planned a clearing operation near Pokrovsk for about a month, their deputy commander said in remarks relayed by Army Inform. The Defense Ministry’s news agency published them on 12 October. He also described the Russian infantry the marines captured as barely trained, hungry, and unwilling to fight.

Russia seized Pokrovsk by seeping small infantry groups into the city a few at a time. Beyond the city, Russian advances stayed limited. ISW assessed on 25 February that the capture brought no further operationally significant gains. Small advances continued, and DeepState mapped one near Bilytske in Donetsk Oblast on 7 October. Every stretch where Ukrainian units stop that infiltration closes the route Russia used to take the city.

What the operation produced

Karyi, the 40th Separate Marine Brigade’s deputy commander, said that Operation Audit cleared about 6 km². The marines suffered no losses while inflicting them on the Russians, he said, and gathered a lot of intelligence. He promised the enemy many more surprises.

The brigade had announced an operation by the same name on 26 September. It said then that the marines had cleared 5 km² and captured two Russian soldiers. The brigade also said they had stopped the flow of Russian infiltration on that stretch of the Pokrovsk direction.

Two weeks of training, then the front

Karyi called the two prisoners typical of the Russian infantry now sent against the marines, with all of two weeks’ training behind them. He said Russian recruits spend a month on transfers and paperwork before going into battle. They then walk to their positions for one or two weeks.

If drones or Ukrainian ground groups don’t kill them first, he said, they surrender because they no longer want to fight. They are not fed or given water. He described one parcel a week with a can of stewed meat, and water drunk from the ground underfoot. That, Karyi said, is why the Russian troops facing the marines are demoralized and untrained.

Russia is concentrating missiles on a smaller, more specific set of targets, and its jet-powered attack drones are part of the reason, the Institute for the Study of War (ISW) assessed. Its combined attack overnight on 7 October killed 22 people in Pryluky, the State Emergency Service (SES) said as of the morning of 8 October. Russian milbloggers noted the shift the same day.

Russia often uses concentrated drone and missile strikes to overwhelm localized Ukrainian air defenses and destroy urban centers, ISW noted. Pryluky, where the strike killed children, was one of the areas a Russian channel says drew a significant share of the Kh-101s that night. With winter close, ISW expects the same pattern against Ukraine's energy grid, with jet drones partly letting Russia keep its missiles for priority targets without firing many more.

Missile waves on a few areas, Russian channels claim

Russia launched 48 Kh-101, Iskander-K, and Kalibr cruise missiles overnight on 7 October, Ukraine's Air Force reported. It also fired ballistic missiles, Zircon and Oniks anti-ship missiles, and 130 strike and decoy drones, 46 of them jet-powered Shahed-type models.

Russian milbloggers claimed the same day that Moscow had grouped a large part of its missile salvo into repeated waves on a few areas, while other weapons kept stretching Ukraine's air defenses elsewhere. The pro-war Russian Telegram channel Dva Mayora described the change as a switch from striking with splayed fingers to a series of hits with missile "fists." Defenders must then absorb a sharply rising load around one chosen site as one wave follows another, the channel claimed.

Citing Ukrainian monitoring channels, it claimed that roughly 30 or more Kh-101 cruise missiles flew toward Pryluky, Kremenchuk, Svitlovodsk, and Oleksandriia in Chernihiv, Poltava, and Kirovohrad oblasts. It put the Kremenchuk group at up to 15 missiles, Kh-101s and Kalibrs among them, aimed at the area of Kremenchuk and its hydroelectric plant.

Jet drones take some of the load off Russia's missiles

ISW said the jet-powered versions penetrate Ukrainian air defenses deeper and more reliably than propeller models. In ISW's assessment, that partly lets Russia concentrate cruise and ballistic missiles on priority targets without significantly raising missile use. Russia builds about 3,000 Geran-4 and Geran-5 jet drones a month, Ukraine's military intelligence agency (HUR) told Militarnyi in August.

ISW expects Russia to apply the pattern in a likely brutal winter campaign against energy infrastructure. Russia likely intends to make city life untenable and force Ukraine to capitulate to its demands, ISW assessed. Such tactics have not worked before and are unlikely to work now, analysts added.

They called cheap countermeasures to jet drones and small cruise missiles vital, alongside Western air defense aid such as US-made Patriots, which can stop ballistic missiles. Ukraine has already paired a Soviet-era Kub launcher with American RIM-7 interceptors to catch jet drones.