Over the course of the Russian invasion of Ukraine, which began in February 2022, irregular military units began to play a more prominent role in the fighting, alongside the regular Russian Armed Forces. In the face of waning recruitment levels for the military as casualties mounted, the Russian government increasingly turned to a variety of mercenaries, militias, paramilitaries, and mobilized convicts. In a similar fashion to the pro-Russian people's militias in Ukraine such as the DPR People's Militia and LPR People's Militia, the combat effectiveness of these irregular combatants varies greatly. This can be seen in the contrast between the poorly equipped and virtually untrained prisoners serving under Storm-Z and the professional mercenaries of PMC Wagner. The Wagner group itself also used convicts in its ranks, alongside its more experienced cadre of fighters. The organization garnered much notoriety as it took up an increasingly prominent role in the fighting in late 2022, culminating in the Battle of Bakhmut.