TAPA, Estonia—The AMX-10 RC tank destroyer has been deployed to far-flung battlefields in Afghanistan and counterterrorism operations in Mali. Now, they’re being deployed as part of a French combined arms squadron to Estonia, near the Russian border, to train with NATO forces and flex the Western alliance’s muscles against neighboring Russia. For decades, Russia amassed the bulk of its advanced military forces in the so-called Western Military District, hunkered down on NATO’s borders, including near the Baltic States. Now, many of those forces have been thrown into the meat grinder in Ukraine, where Russia’s army has suffered devastating losses that could take decades to rebuild. But even as the war drags on in Ukraine, Russia plans to rebuild its forces facing its new and expanded frontiers with NATO, according to interviews with multiple Eastern European defense and military officials. Officials in Washington may be sanguine about the longer-term threat from a Russia that has sowed Ukrainian fields with conscript bodies, but in Eastern Europe, and especially the Baltics, things still look dicey. Russia could fully reconstitute the number of troops facing the Baltic countries in a matter of two months to two years, these officials said, posing a new threat of a Russia-NATO military showdown even if the conflict in Ukraine isn’t resolved. Even if the troops and equipment won’t be of the same quality as those deployed to the region before the war, defense officials say they would be sizable enough to carry out an incursion into NATO territory—making units like the French combined arms squadron all the more significant for their deterrence value.

“Russia has plans to increase considerably the number of forces behind the Estonian and Latvian borders,” said Tuuli Duneton, undersecretary for defense policy at the Estonian Ministry of Defense. “According to our assessments, Russia is going to be able to reconstitute its forces in two years,” with the potential to launch a limited incursion against NATO, she said. For now, the Russian forces facing NATO’s vulnerable northeastern flank represent a skeleton crew of what was once there. Russia’s hopes for a quick victory in Ukraine were dashed thanks to military incompetence and effective Ukrainian resistance, forcing Moscow to rush troops from areas far north of Ukraine into the battlefield. But Russia’s ability to mobilize fresh troops, even poorly trained conscripts and reservists with aged equipment, showcases a capability that has alarmed military planners in Europe. Russian President Vladimir Putin has so far shown no interest in expanding the war to NATO, protected by the alliance’s nuclear umbrella and collective defense clause among its 31 members, though he has rattled plenty of nuclear sabers. But that could change in the future, defense officials say, particularly if Putin senses military weakness on NATO’s eastern flank and smells an opportunity.