Drones hit oil depots and a refinery, sparking huge fires. Explosions derailed not one but two freight trains. For the past several days, Russian infrastructure near Ukraine’s border and in Russian-controlled Crimea has been targeted repeatedly.
Ukraine has not directly claimed responsibility for the strikes, the latest of which appeared to hit an oil refinery in the Krasnodar region of southern Russia on Friday, according to Russian state media. But the increase in the tempo of attacks could help set the stage for a counteroffensive that Ukrainian officials have said is about to begin, according to military analysts.
Though far beyond the front lines of the war, the strikes put Russia’s logistics under pressure, forcing Moscow to expend additional resources rebuilding damaged infrastructure and complicating planning for Russia’s defenses against the counteroffensive, analysts say. And they also have a psychological effect, puncturing Moscow’s aura of invincibility on territory it controls, they say.
“It’s part of the preparation of the battlefield,” said Yohann Michel, a research analyst at the International Institute for Strategic Studies. “You’re weakening the body of the enemy in different places in order to make sure that they are not moving at the moment when you actually attack.”
Such attacks are not designed primarily to hit at the point of a future counteroffensive, he said. Ukraine’s push to retake territory, if it happens, is expected to focus on lands Russia has seized since the start of its full-scale invasion more than 14 months ago, including in the eastern Donbas region and the southern regions of Kherson and Zaporizhzhia.
But Crimea, the Ukrainian peninsula that Russia illegally annexed in 2014, has been a key conduit for supplies and troops supporting Russia’s occupying forces in southern Ukraine, and it has been hit repeatedly in recent months. Ukraine has broadly claimed responsibility for strikes in Crimea, though it rarely gives details. But it has usually maintained ambiguity about involvement in attacks on Russian territory.
Mr. Michel said strikes on infrastructure far from the front lines aim to create bottlenecks in the military supply chain, forcing Russia to divert resources and energy to cover the gaps, which in turn exposes other areas.
The hits have multiplied in recent days. On Friday, a drone attacked the Ilsky oil refinery in Russia’s Krasnodar region for the second consecutive day, Russia’s state news agency, Tass, reported. A fire broke out but was extinguished and there were no casualties, it said.
Russian officials reported strikes on train lines in Russia’s Bryansk region on Monday and Tuesday. The region was a staging ground for the invasion in February of last year and has since been used as a launch point for drone strikes on Ukraine.
There was also a fire on Saturday in Crimea, which Russia annexed illegally in 2014. Four drones also attacked storage facilities on Thursday at one of the largest oil refineries in southern Russia’s Krasnodar Territory, according to Tass, the Russian state news agency.
A British defense intelligence report on Thursday said that the “disruption to the fuel storage and distribution network will likely force adjustments to Russia’s military refueling operations to mitigate targeting.”
In one measure of Crimea’s importance for Russian military logistics, the mayor of the occupied city of Melitopol in southern Ukraine said last month that just under one-third of the supplies that pass through the city destined for Russian forces come from Crimea.
Western allies have urged Ukraine not to use newly supplied, long-range weapons to strike inside Russia, for fear that such attacks could provoke the Kremlin into escalating its war. Analysts say that Ukraine has developed a fleet of drones that can travel hundreds of miles carrying munitions. And Russia’s air defenses are set up to protect its long border against aircraft and much larger missiles, according to Samuel Bendett, a Russia expert at CNA, a research institute in Virginia.
Mr. Bendett said that one benefit for Ukraine of staging drone strikes would be to force Russia to reveal the location of its air defense systems, making them vulnerable to future attack.
In addition, any strikes in Russia can cause “serious psychological trauma” and dent Moscow’s feeling of control over its own territory, said a Ukrainian colonel, Petro Chernyk, who was careful not to suggest that the Ukrainian military was behind the recent attacks.
“Everything that is happening on the territory of the Russian Federation in terms of the destruction of fuel and lubricant materials and any other valuable materials that ensure the war is incredibly good,” he told reporters on Wednesday.
Marc Santora contributed reporting.
