Why couldn't Russia stop Ukraine from attacking Kursk?

Russia continued to send reinforcements but Ukraine maintained a strong counter-offensive campaign, putting great pressure on the defense line in Kursk.

On the Sumy-Kursk front, the Russian and Ukrainian armies had not deployed combat forces for a long time. It was not until the Ukrainian army (AFU) suddenly raided Kursk that both sides increased their strength and each side maintained the size of an army group, consisting of several tens of thousands of combatants.

Such a large number of troops would certainly need to be assembled and mobilized from many other places. After all, on a front of more than 1,000 km, neither the Russian nor the Ukrainian armies have much spare capacity to easily mobilize tens of thousands of mobile troops.

The Ukrainian Armed Forces (AFU) mainly used troops transferred from the north of Kharkiv. After the Russian Armed Forces (RFAF) reopened the "North Kharkiv" front in May 2024, the AFU immediately sent reinforcements to defend this front, so it concentrated a lot of mobile forces here.

But it was clear that this number of troops alone was not enough. To strengthen the cross-border assault force, the AFU then mobilized elite troops from various fronts (especially heavy armor and special forces), to further strengthen the fighting force in Kursk.

On the RFAF side, in addition to mobilizing conscripts and North Korean troops to fill the gap, the Russian RFAF General Staff also mobilized paratroopers, marines, and special forces, mainly from Zaporizhia, Chasov Yar, and Seversk. In addition, the 34th Mountain Motorized Infantry Brigade from Kherson was reinforced.

The 34th Mountain Motorized Infantry Brigade is part of the 49th Army of the Southern Military District of the RFAF. In the early days of the Russo-Ukrainian War, the unit was part of the Southern Army Group and took part in the offensive north of Kherson, occupying a large area.

After the AFU launched the Kherson counteroffensive in October 2022, Russian troops retreated to the east bank of the Dnieper River. At this time, to protect the east bank of the Dnieper River, the RFAF General Staff established the Dnieper Army Group, responsible for defending the Russian-administered Kherson Oblast and operations in Zaporozhye. The 34th Brigade remained on the riverside defense line for more than two years.

In November 2023, the AFU launched an operation to cross the Dnieper River and seize the Krynki bridgehead; however, this was not the 34th Brigade’s defense area, so the Brigade did not participate in combat. The Brigade only had to guard against infiltration by small reconnaissance groups and sporadic artillery and FPV UAV attacks by the AFU.

Due to the lack of combat missions, the 34th Mountain Motorized Infantry Brigade remained largely intact. After the AFU crossed the border to attack Russia's Kursk Oblast in August 2024, the Brigade was transferred to this front in early 2025, tasked with serving as a mobile strike force.

Immediately after entering combat on the Kursk front, the 34th Mountain Motorized Infantry Brigade asserted its combat power, not only in defense but also in attack, when it captured a number of important villages such as Pogrebki and participated in the breakthrough campaign into Sudzha, the AFU stronghold in the Kursk region.

After the AFU suffered a heavy defeat at Kursk, in order to disperse the Russian army and prevent it from directly attacking Sumy Province, the AFU sent its elite forces to attack Russia's Belgorod Province. In fact, although the AFU seemed to have opened a new front, because the fighting area, although in another province of Russia, bordered Kursk Province; this was actually a secondary battlefield of Kursk Province.

To attack Belgorod, the AFU General Staff did not transfer additional troops from elsewhere, but continued to use mobile troops in Sumy. Although it was only a secondary battlefield, the AFU deployed many elite forces there, including the 47th Motorized Infantry Brigade, fully equipped with American heavy weapons, the 33rd Assault Brigade, and the 225th Special Forces Brigade.

Therefore, it can be seen that on the Belgorod front, there were a large number of Bradley M2A2 infantry fighting vehicles in the AFU attack formation; besides a number of Weasel infantry fighting vehicles provided by Germany. In addition, the 47th Mechanized Infantry Brigade also risked using M1A1 tanks for support, but after one was destroyed, they did not dare to use it again.

No longer caught by surprise like when the AFU attacked Kursk in August 2024, the RFAF in Belgorod placed dragon teeth and mine obstacle belts on the Belgorod border defense line. Therefore, the AFU assault forces here were reinforced with many mine-clearing engineering vehicles to achieve a breakthrough.

In addition, to help the infantry fight more effectively, the Ukrainian army also learned from the RFAF, when equipping the assault infantry with a number of all-terrain vehicles, to participate in offensive operations to overcome obstacles. In the face of fierce attacks by the AFU, they also approached and at times even controlled the villages of Popovka and Demidovka in the Belgorod region.

However, the Russians then used FPV UAVs and artillery units to launch a fierce attack on the Ukrainian forces at Popovka and Demidovka. After losing a large amount of weapons, the AFU’s ability to continue replenishing its troops was no longer sufficient. The RFAF took this opportunity to deploy infantry to push the Ukrainian forces back across the border.

The first Russian infantry force to reinforce the Belgorod front was the 155th Marine Brigade. After that, the 155th Brigade left only the UAV unit to continue fighting, while the infantry was withdrawn to the rear to rest. The ground combat force was handed over to the 34th Mountain Motorized Infantry Brigade to take over.

The 34th Brigade’s fighting style was quite good; they organized defenses, preventing the Ukrainians from breaking into the villages. As for clearing the vast dense forests in the border area, they used UAVs to effectively clear them. This tactic gave the Ukrainians a “headache”.

The key point here is that the 34th Mechanized Infantry Brigade is not the RFAF’s “premium workhorse.” But it has “competed well” with the AFU’s “workhorses,” such as the 47th Mechanized Infantry Brigade, the 33rd Assault Brigade, and the 225th Commando Brigade.

The important thing is that the AFU was at a disadvantage when it had to waste such numbers of troops and equipment for such a long time; and the AFU's elite mobile forces were held back where they should not be held back; even contributing to the achievements of "mediocre" units such as the RFAF's 34th Motorized Infantry Brigade, a unit that had not been very famous in the RFAF since the beginning of the war. (photo source Ukrinform, cm163.com, TASS).

Source: https://khoahocdoisong.vn/vi-sao-nga-khong-ngan-duoc-ukraine-tan-cong-kursk-post1544064.html