Putin builds strategic reserve for possible NATO clash, ISW warns

Vladimir Putin appears to be preparing for a direct confrontation with the NATO alliance by building a strategic reserve of new Russian military recruits, according to analysts and an insider source cited by the Institute for the Study of War. The source said that approximately 292,000 people signed contracts with the Russian Ministry of Defence from the start of 2025 through Sept. 15, an average of about 7,900 per week. Some of those recruits are said to be part of a strategic reserve the Kremlin has been assembling since early July 2025. The Institute for the Study of War (ISW) noted that a decline in Russian casualties over the summer could have created the space for Moscow to pursue a larger pool of trained personnel, potentially ready for staged deployments if a wider war were to unfold. ISW researchers stressed that the reports imply the Kremlin remains intent on achieving its aims on the battlefield in Ukraine and may be planning for a possible Russia-NATO conflict in the future. They pointed to the broader context of a push to recruit Russian youth into military programs in the years ahead as part of the strategy to sustain long-term military capacity.

The developments come despite public signals from Moscow aimed at diplomacy, including a pledge to adhere to the New Strategic Arms Reduction Treaty (New START) for one year after its expiration next February. On the European border, however, tensions have persisted. British home secretary Yvette Cooper said Monday that British jets were prepared to confront Russian aircraft violating NATO airspace following a series of incursions over the past two weeks. Estonia later reported that three Russian fighter jets violated its airspace, a claim Russia denied. The incursions have occurred against the backdrop of Russia’s joint Zapad drills with Belarus near the NATO border. Observers note that Moscow has used exercises like Zapad to gauge readiness and to project a broader signaling of military intent, a pattern analysts have linked to earlier operations before Russia’s wars in Georgia in 2008 and Ukraine in 2022.

Natia Seskuria, an international security expert and associate fellow at the Royal United Services Institute, told the Daily Mail that Russia has historically used such drills to test how different war-game scenarios might play out and to demonstrate that Moscow’s plans extend beyond Ukraine. “We know that Russia has used these drills to sort of test different war game scenarios. In 2008 against Georgia and then against Ukraine, Zapad drills preceded the actual military operations, the wars that Russia has launched against these countries,” she said. The scale of Zapad this year was smaller than in 2021, but Seskuria argued that the drills still serve as a vehicle for signaling that Russia’s ambitions are broader than the Donbas or Ukraine alone. “The scale is much more reduced. But it’s also an opportunity for Russia to basically test different scenarios and also to demonstrate to the West that they are still committed to their plans,” she said.

The fighting in eastern Ukraine remains brutal and protracted. Russian forces have suffered heavy losses after more than three and a half years of war, with Western assessments from last summer estimating Russian casualties in the hundreds of thousands and Kyiv intelligence warnings of significant demographic consequences for Russia if the war continues. Putin has maintained that there are still more than seven hundred thousand Russian personnel on the frontlines, a figure that underscores Moscow’s ongoing manpower challenges as it presses for gains in Donetsk. In Donetsk, Russia has controlled roughly seven of the region’s ten districts, with Ukrainian forces holding the fortress belt around four cities that have resisted major Russian advances for years. The fighting has intensified as Moscow seeks to sever Ukrainian supply lines and push around fortified city centers, a strategy that aims to force a strategic collapse rather than a direct assault on heavily defended urban areas.

The Donetsk belt has become the epicenter of the current phase of the war. Ukrainian commanders describe the landscape as a scanner’s map of risk: Russian forces attempt deep flanking maneuvers and infiltration tactics that test frontline cohesion and command, often slipping small units between regularly rotated units. Col. Pavlo Yurchuk, defending a northern node near the fortress belt, said that while such maneuvers may appear sound on a map, experience shows they are not Russia’s preferred method of war. “From a military point of view it looks correct – on the map it looks neat – but after nearly three and a half years of war we all know that such deep maneuvers and wide flanking operations are not Russia’s forte,” Yurchuk said. He cautioned that Russia’s tactics were slow to convert into lasting gains and that supply lines and local control would be the decisive bottlenecks in any advance.

Ukraine’s leadership has repeatedly warned that Moscow’s manpower constraints could become an advantage for Kyiv if Kyiv can sustain rotations and leadership across units. Taras Chmut, director of the Come Back Alive Foundation, which has raised hundreds of millions of dollars to equip Ukrainian forces, said that the problem is as much managerial as it is numerical. He described a systemic gap where brigades list thousands of soldiers on paper but can field only hundreds in combat. “Not only the quantity, but their dispersion on the battlefield, the inefficiency of command, and the shortcomings in training and management” create a structural weakness that Kyiv is attempting to counter with technology and disciplined logistics. He stressed that even if Ukraine can muster larger reserves, the current organizational problems must be addressed at the rear or the war could grind on without meaningful relief.

Analysts warn that, even if Russia makes limited gains in the Donetsk region, the broader war will not end soon. Nick Reynolds, a research fellow in land warfare at the Royal United Services Institute, warned that the longer the war drags on without systemic reforms, the more Russia may be able to leverage its manpower and equipment advantage. “The longer this drags on, the worse it will get – and without fresh resources the Russians will simply outmatch us in quantity and means,” he said, underscoring the persistent stress on Ukrainian forces. He added that even if Moscow captures large portions of Donetsk, it does not guarantee a rapid resolution to the conflict. “I see absolutely no reason, no indication why the Russian Federation or the Russian Armed Forces would stop” with the Donetsk region, Reynolds said, signaling that the war could continue into a broader struggle even if Moscow achieves some battlefield success.

For Kyiv, the immediate concern remains maintaining manpower levels and ensuring regular rotation to prevent fatigue and erosion of capability. Ukrainian officials have cautioned that the war’s human toll is borne not only by combatants but by civilians retrofitting a war economy that bears down on regional populations. If Russian gains continue to consolidate around the fortress belt, the risk of displacement and infrastructure damage could escalate, with consequences for Ukraine’s eastern plains and the surrounding regions.

The latest signals from Moscow, including the surge in volunteer and contracted recruitment and the ongoing Zapad-2025 exercise, suggest that Russia intends to preserve a considerable and ready fighting force for a potential broader confrontation. Washington’s assessment in recent months has stressed that Moscow seeks to deter Western security guarantees in Europe while testing NATO cohesion. The international dynamics surrounding Russia’s military strategy, including its legal commitments under arms-control regimes, will likely shape the next phase of the conflict as both sides prepare for a protracted struggle that could extend beyond Ukraine’s borders. As the Kremlin balances public diplomacy with aggressive posturing, analysts say the strategic reserve could become a pivotal factor in any future confrontation—whether through a rapid, decisive clash or a drawn-out campaign where manpower, logistics, and command decisions determine the outcome.