Battle in the Russian invasion of Ukraine. Sep-Oct 2022.
A major Ukrainian counteroffensive operation began on 6 September 2022, during the Russian invasion of Ukraine. Following the launch of the Kherson counteroffensive in southern Ukraine in late August, Ukrainian forces began a second counteroffensive in early September in Kharkiv Oblast, in eastern Ukraine.
During the offensive, Ukraine retook over 500 settlements and 12,000 square kilometers of territory in the Kharkiv region.
Background.
During the early days of the Russian invasion of Ukraine, Russian forces captured much of eastern Kharkiv Oblast, including the towns of Kupiansk, Shevchenkove, and Balakliia. Balakliia itself was captured on 3 March 2022, without much of a fight. From March to early May, most of the fighting in Kharkiv Oblast was concentrated in the cities of Kharkiv and Izium.
In early April, Russian forces captured Izium, and Ukrainian forces successfully defended Kharkiv by early May. After that, the frontline began to stagnate as Russia and Ukraine focused their efforts on the cities of Sievierodonetsk, Lysychansk and the wider Donbas region.
Throughout July and August 2022, Ukrainian and Russian media both amplified claims of a Ukrainian counteroffensive in Kherson Oblast, which finally culminated on 29 August 2022. The counteroffensive saw slow progress, with Ukrainian forces suffering heavy losses and facing a stiff Russian resistance. However, on 6 September, Ukrainian forces launched a surprise counteroffensive in eastern Kharkiv oblast, with fighting for Balakliia beginning on the first day.
Russian offensives in the first months of its invasion of Ukraine left large swathes of Kharkiv Oblast under Russian control, including the key logistical nodes of Izium, Kupiansk, Shevchenkove, and Balakliia. However, the majority of the oblast remained within Ukrainian control, including the city of Kharkiv, where the Russian military continuously bombarded with rockets, artillery, and cluster munitions until August.
Ukrainian forces held off Russian advances towards Kharkiv, then launched counteroffensives in March and May pushing the Russians from the outskirts of the city. By 6 June, the Russian bombardment of Kharkiv had killed 606 civilians and injured 1,248 according to Amnesty International.
The battle lines in Kharkiv Oblast remained largely static over the next few months as Ukrainian and Western military analysts believed Russia lacked the ground forces to renew its offensive. The Kharkiv death toll exceeded 1,000 by August.
By September 2022, Oleksandr Syrskyi, who had been in charge of the defense of Kyiv at the beginning of the invasion and later received the title of Hero of Ukraine for his service, was appointed to command the Ukrainian land forces in Kharkiv Oblast. The counteroffensive was performed under his command, and Syrskyi is considered to be its architect.
Prelude.
After weeks of Ukrainian propaganda about an imminent counteroffensive in southern Ukraine, Russia redeployed thousands of troops, including elite units such as the 1st Guards Tank Army, to Kherson Oblast, leaving its remaining troops manning a "stretched and tired Russian front that spanned some 1,300km – roughly the distance from London to Prague."
The arrival of US-supplied HIMARS guided-rocket artillery enabled Ukrainian forces to strike up to behind Russian lines, targeting Russian bases and ammunition depots as far back as Kupiansk and Kivsharivka in the weeks preceding the eastern counteroffensive. These strikes further weakened Russian logistics and morale.
On 5 September, the Ukrainians claimed to have killed or wounded 100 Russian soldiers and destroyed two combat vehicles in a strike on Kupiansk.
On 29 August, Ukraine announced it would soon launch an offensive in the Kherson region of southern Ukraine. Ukrainian units attacked soon after, and Russia's attention shifted to its Kherson line. While the Kherson offensive might have been genuine, Western analysts view it as part of a ploy to divert Russian forces away from Kharkiv prior to Ukraine's much larger eastern counteroffensive. In any case, Russian forces in Kharkiv were left understrength and unprepared in the days preceding 6 September. 
Russian authorities postponed annexation referendums in Russian-occupied Ukraine on 5 September 2022 due to security concerns.
Counteroffensive.
First phase (6–12 September 2022).
Initial advance.
On 6 September 2022, Ukrainian forces launched a counteroffensive in the Kharkiv region, taking Russian forces by surprise. In a 10 September interview with the Guardian, Ukrainian special forces spokesman Taras Berezovets stated Russia "thought [the counteroffensive] would be in the south... then, instead of the south, the offensive happened where they least expected, and this caused them to panic and flee."
Ukrainian troops advanced at least into Russian-held territory and recaptured some of territory during the first two days.
By 9 September, Ukraine had broken through Russian lines, with the Ukrainian military saying that it had advanced nearly and recaptured over of territory. This advance placed them approximately northwest of Izium, the main Russian logistics base in the region, a rate of advancement largely unseen since Russia withdrew from Kyiv at the start of the war. "The Washington Post" described the fall of Izium on 10 September as a "stunning rout"; the Institute for the Study of War assessed that Ukrainian forces had captured approximately in the breakthrough.
One military expert said that it was the first time since World War II that whole Russian units had been lost in a single battle. Journalist Harald Stutte argued that the commander of the Ukrainian offensive, Oleksandr Syrskyi, had achieved a "tactical masterstroke" during the operation, especially at Lyman. In contrast, the main Russian commander opposing the Ukrainian attack, Alexander Lapin, was criticized for his lacking performance.
Breakthrough.
On 6 September, having concentrated their forces north of Balakliia at Pryshyb, a small village about 15 km northwest of Balakliia, Ukrainian troops launched a counteroffensive in the Kharkiv Oblast, which drove Russian forces back to the left bank of the Donets and Serednya Balakliika rivers. The Ukrainian forces involved were Ukrainian special forces, plus tanks, armoured personnel carriers and troops from the 92nd Mechanized Brigade.
On the same day, Ukrainian forces captured Verbivka, about 8 km east of Pryshyb and less than 3 km northwest of Balakliia. Several Russian sources reported that Russian forces demolished unspecified bridges on the eastern outskirts of Balakliia to prevent further Ukrainian advances. Ukrainian forces went around Balakliia in order to besiege it. Some Ukrainian forces stayed near Balakliia, fighting Russian forces in the center of the city while another group went north towards Volokhiv Yar.
Ukrainian troops then went on the offensive in the directions of Balakliia, Volokhiv Yar, Shevchenkove, Kupiansk and the areas of Savyntsi and Kunye, situated east of Balakliia. According to Russian sources on this line of contact Ukrainians were opposed in some areas of the line by lightly armed forces of the DPR Militia, while Ukrainian sources said that the forces in this region were professional Russian soldiers, not conscripts from the Donbas.
By the following day, Ukrainian forces had advanced some into Russian-occupied territory, recapturing approximately , and reaching positions northeast of Izium. Russian sources claimed this success was likely due to the relocation of Russian forces to Kherson, in response to the Ukrainian offensive there.
By 8 September, Ukrainian troops had advanced deep into Russian defensive positions north of Izium. SOBR units of Russian National Guard forces lost control of Balakliia, about 44 km northwest of Izium, although Ukraine did not establish control of the city until 10 September. Near the city, Ukrainian forces recaptured the largest ammunition storage base of the Central Rocket and Artillery Directorate of the Armed Forces of Ukraine. Ukrainian forces also regained control over more than 20 settlements. On the same day, Ukrainian media reported that Ukrainian forces captured a high-ranking Russian officer on the Kharkiv front. Based on footage of the man, it was speculated that he was Lieutenant General Andrei Sychevoi, Commander of the Western Military District of the Russian Armed Forces. Russian occupation authorities in the city claimed that Russian forces began to defend Kupiansk. On the morning of 8 September, Ukraine's 80th Brigade reached the Oskil River at the village of Senkove.
On 9 September, the Russian-backed administration ordered the evacuation into Russia of the population from Izium, Kupiansk and Velykyi Burluk. Local residents later reported that at this point Russian soldiers in the area began to flee villages, leaving behind their weaponry, before Ukrainian troops even arrived. Later in the day Ukrainian forces reached Kupiansk, a vital transit hub at the junction of several of the main railway lines supplying Russian troops at the front. The Institute for the Study of War said it believed Kupiansk would likely fall in the next 72 hours. In response to the Ukrainian advance, Russian reserve units were sent as reinforcements to both Kupiansk and Izium.
On 10 September, Ukrainian forces retook Kupiansk and Izium, and were reportedly advancing towards Lyman. An advisor to the head of Kharkiv regional council, Natalia Popova, posted photos on Facebook of the 92nd Mechanized Brigade's 1st Mechanized Battalion holding a Ukrainian flag outside Kupiansk city hall. Ukrainian security officials and police moved into the recaptured settlements to check the identities of those who stayed under Russian occupation. Later that day, Luhansk Oblast Governor Serhiy Haidai claimed that Ukrainian soldiers had advanced into the outskirts of Lysychansk, while Ukrainian partisans had reportedly managed to capture parts of Kreminna. Haidai stated Russian forces had fled the city, leaving Kreminna "practically empty".
The "New York Times" said "the fall of the strategically important city of Izium, in Ukraine's east, is the most devastating blow to Russia since its humiliating retreat from Kyiv." The Russian Ministry of Defence spokesperson Igor Konashenkov responded to these developments by claiming that Russian forces in the Balakliia and Izium area would "regroup" in the Donetsk area "in order to achieve the stated goals of the special military operation to liberate Donbas". Ukrainian President Zelenskyy said that "The Russian army in these days is demonstrating the best that it can do — showing its back. And, of course, it's a good decision for them to run." He claimed that Ukraine has recaptured since the start of the counteroffensive.
On 11 September, "Newsweek" reported that Ukrainian forces had "penetrated Russian lines to a depth of up to 70 kilometers in some places and retaken more than 3,000 square kilometers of territory since September 6".
Reports that Russian troops had withdrawn from Kozacha Lopan and locals had raised the Ukrainian flag next to the town hall came in from local Ukrainian officials. A map used in the briefing of the Russian Ministry of Defense on the same day confirmed that Russian forces had withdrawn from Kozacha Lopan, as well as Vovchansk and other settlements on the Ukraine-Russia border. Ukrainian forces also retook Velykyi Burluk. The counteroffensive stalled after 12 September, as news teams, Ukrposhta, and other organizations were let into eastern Kharkiv oblast.
"Financial Times" attributed western-supplied HIMARS as one of the reasons that enabled Ukraine to overpower Russian forces in merely 6 days, over a span of 90 km (roughly the distance between London and Cambridge), and recover more than 2,500 km2 of land.
Russian withdrawal from Kharkiv Oblast west of Oskil River.
In the afternoon of 11 September, the Russian Ministry of Defense announced the formal pullout of Russian forces from nearly all of Kharkiv Oblast. The ministry "announced that an 'operation to curtail and transfer troops' was underway." At 20:06 that day, Russian Kalibr cruise missiles struck Ukrainian critical infrastructure sites (including Kharkiv TEC-5), which left Poltava, Sumy, Kharkiv, Dnipropetrovsk, Donetsk, and parts of Odesa Oblasts without electricity. Meanwhile, clashes between Ukrainian attackers and Russian defenders continued at Lyman.
On 12 September, according to the summary of the General Staff of the Armed Forces of Ukraine, the Ukrainian Defense Forces cleared Russian troops in more than 20 settlements, most noticeably in Velykyi Burluk and Dvorichna. The Russian head of the Kharkiv occupation authority, Vitaly Ganchev, revealed on Russian state media Russia-24 that Ukrainian forces outnumbered Russian forces by "8 times". The border with the Russian Belgorod Oblast has been closed after some 5,000 civilians were "evacuated" to Russia.
Ukrainian forces retook all of Kharkiv Oblast west of the Oskil River by 13 September, with media claiming that Ukrainian troops had entered Vovchansk.
Other gains and casualties.
In the morning of 11 September, Luhansk Oblast Governor Serhiy Haidai claimed that Russian forces had mostly left Starobilsk. In the same message, he claimed that Russian occupational authorities were also leaving from areas that Russia had controlled since 2014, though there was no clear evidence to verify this claim.
On 12 September, Ukraine's National Guard liberated Sviatohirsk, which Russian forces captured in June 2022, and inched closer to the administrative border between Kharkiv and Donetsk Oblasts as well