Russia is bolstering its military presence on its western border, sending tens of thousands of soldiers to newly built installations within easy striking distance of Ukraine.
The moves, which come as Moscow ratchets up confrontation over the Black Sea peninsula of Crimea, are a centerpiece of a new military strategy the Kremlin says is meant to counter perceived threats from the North Atlantic Treaty Organization.
Military analysts say the deployments appear to be an effort to build a more permanent and robust military posture around Ukraine, where Russia has carried out covert military interventions aimed at maintaining influence in its West-leaning neighbor.
“Russia’s plans around the Ukrainian border show a real intent to use force if needed,” said Anton Lavrov, a defense analyst at Moscow-based think tank CAST. “They would be Russia’s first line of assistance if the pro-Russian rebels in east Ukraine needed help.”
The Russian Defense Ministry didn’t respond to emailed questions.
Tensions between Russia and Ukraine have flared in recent days after Russian President Vladimir Putin accused Ukraine’s military of killing two Russian service members during incursions into Crimea, which Russia annexed from Ukraine in 2014. Mr. Putin said Russia would respond to the deaths. Ukrainian officials denied the charges, saying Russia was creating a pretext for further intervention.
Outside the region, Russia has begun using Iran as a launchpad for airstrikes in Syria, further underscoring its assertive military strategy.
The buildup on Ukraine’s frontier represents a significant shift. For years, the Russian-Ukrainian border was viewed by Moscow as little more than an administrative boundary. As late as 2009, Russia didn’t have a single large army unit along its 1,200-mile border with Ukraine. That changed with the 2014 revolution in Kiev and subsequent conflict in eastern Ukraine.
As that conflict unfolded, Russia stationed tens of thousands of troops on the border in makeshift camps and fomented a pro-Russian rebellion with deliveries of weapons and volunteer footsoldiers.
At key points during fighting, regular Russian military units helped to prevent the Ukrainian army from routing the separatists, though Moscow denies sending conventional forces into Ukraine.
Violence in eastern Ukraine continues, despite cease-fire attempts brokered by European leaders. July and August saw some of the worst flare-ups in months, with Ukraine saying Thursday that three soldiers had been killed in the previous 24 hours.
Now Russia is building new army installations along the border, creating some new units and redeploying others from further east, in line with its telegraphed intentions to step up forces in the country’s west.
In May, Russian Minister of Defense Sergei Shoigu said the army would create three new divisions to counter NATO, which in April announced it would sent four battalions, or about 4,000 troops, to Poland and ex-Soviet Baltic countries.
“The political situation along the western border of the country remains unstable,” Mr. Shoigu told officers at a televised meeting in June, noting that the U.S. and other NATO members are boosting their military potential in the region.
Military officials said two divisions would be created in the Western Military District and one in the Southern Military District, each with 10,000 troops. The focus has also been on combat readiness: Russia has carried out more than 300 training exercises and war games in the Western Military District since the winter.
Several units are being relocated to the region, including those in the Western Military District’s 20th Army, which had been based until last year in Nizhny Novgorod, east of Moscow.
The 20th Army, which had seen lower levels of readiness in previous years, is also getting a major overhaul with new combat units, including two or three motorized rifle brigades and a tank brigade.
A new regional headquarters is now located in Voronezh, some 100 miles from the border with Ukraine. To make way for its relocation, new bases and at least 10 military barracks are being constructed in nearby towns for the incoming soldiers. Construction of some of the new installations began in 2015.
Russia is preparing to hold major annual military exercises, called Kavkaz 2016, near the Ukrainian border in September.
The exercises are the first to be aimed at integrating Crimea and the peninsula’s defense into Russian military plans.
A U.S. military official said Russian units are expected to practice conducting amphibious landings and air defense exercises to reinforce Crimea. U.S. officials also anticipate Russia will continue to rotate troops and equipment, with long convoys of military material moving in and out of the region.
Capt. Danny Hernandez, the chief spokesman for U.S. European Command, said the U.S. was monitoring the region and the planned Russian military exercises closely.
Ukrainian officials have become increasingly nervous about growing violence in the eastern part of Ukraine.
Ukrainian President Petro Poroshenko said Thursday that there had been record levels of artillery shelling against Ukrainian positions the previous night, adding that Ukraine might announce mobilization and martial law if the conflict escalates in Crimea and the east.
U.S. and other allied officials believe Russia’s strategy is to provoke an overreaction by Kiev, one that could help undermine the case in Europe for sanctions.
“Russia wants to show it can turn the heat up and down and put pressure on Kiev to react,” a Western official said.