The 84th Motor Rifle Division has been formed within russia’s 3rd Combined Arms Army, formerly the 1st Army Corps of the so-called "LPR." The 4th Motor Rifle Brigade became the core of the new division, which Russian forces have deployed in the fighting for Kostiantynivka.
The relevant information was reported by the Unit Observer account on X. Defense Express notes that this is the first report in 2026 of a new division-level formation being established in the russian military.
Read more: Ukraine's Nemesis Brigade Destroys Five russian Radars, Three Air Defense Systems (Video)
Looking at the previous years, there were reports in 2025 of three new divisions being formed from existing brigades.
In June 2025, reports emerged about the possible formation of a new 71st Division based on the 200th Brigade. Then, toward the end of the year, there were reports about the formation of two naval infantry divisions, although these reorganizations had reportedly been planned two years earlier.
The emergence of one new division in 2026, compared with three in 2025, represents a relatively low rate of new division formation. By comparison, seven new divisions were reportedly formed in 2024. This came against the backdrop of the russian Army expanding from 12 divisions in 2022 to 23 by early February 2025.
At the same time, the organizational structure of russian motor rifle divisions has undergone changes during the full-scale war. Before February 2022, the core of such formations consisted of one tank regiment and two motor rifle regiments.
During the formation of new divisions in 2024–2025, however, the structure shifted to three motor rifle regiments and one tank battalion.
The aforementioned 4th Motor Rifle Brigade had two attached motor rifle regiments, which also became part of the core used to form the new 84th Motor Rifle Division.
This erosion of the traditional structure is directly linked to two obvious factors: russia’s heavy losses of armored and other heavy equipment, as well as its high personnel losses.
Read more: russia Equips New Geran-5 Drones With Kh-101-Style Navigation: Why Darkness Could Be Problem
