Russia said it is preparing "massive strikes" against Ukraine's energy infrastructure in retaliation for Kyiv's attacks on Russian economic targets, raising the prospect of another campaign against the country's power system as Ukrainian officials warn Moscow could mobilize as many as 300,000 troops for a winter offensive.

The Russian Ministry of Defense said the military had received instructions to prepare attacks targeting Ukrainian energy facilities, explicitly linking the planned operation to Ukraine's expanding use of long-range weapons against infrastructure and businesses inside Russia.

"In accordance with the received instructions, the Armed Forces of the Russian Federation began preparing to launch massive strikes against Ukrainian energy facilities as a response to the continuing attacks of the Kiev regime against the Russian civil infrastructure and fuel and energy facilities," the Russian Ministry of Defense said in a social-media post.

The warning follows significant Russian attacks already carried out against Ukraine. Ukrainian President Volodymyr Zelenskyy said emergency crews were responding to extensive damage in Myla in the Kyiv region after a Russian strike and subsequent explosions.

"Work continues in the village of Myla in the Kyiv region to eliminate the consequences of the Russian strike. Rescuers managed to extinguish most of the fires," Zelenskyy wrote on social media.

"Unfortunately, it is known that 38 people died from the strike and subsequent detonation. My condolences to the relatives and friends. Twenty people were injured, including two children. Four are considered missing," he added.

Zelenskyy said the recent attacks appeared designed to wear down Ukraine's air defenses and population through sustained waves of drones. Kyiv has faced a particularly intense barrage in recent days, according to the Ukrainian president.

"Now the Russians' tactics are to exhaust Ukraine, to exhaust Ukrainians, primarily our people. There are constant drone attacks - many jet "shaheeds". Our soldiers shoot down a significant part. There were almost one and a half thousand drones of all types in these four days alone," Zelenskyy said.

The Russian threat against Ukraine's energy system comes as Kyiv increasingly attempts to shift some of the economic costs of the nearly five-year war onto Russian territory. Ukraine has expanded its use of longer-range weapons against targets it says contribute to Moscow's military and logistical capabilities.

Earlier this month, Ukrainian forces repeatedly struck facilities associated with Russian online retailers Wildberries and Ozon. Kyiv has argued that the companies' logistics networks play an important role in supplying Russia's war effort, making their facilities legitimate targets in its campaign to disrupt military supply chains.

Russian President Vladimir Putin responded to the attacks by accusing Ukraine of opening "Pandora's box" through strikes on economic targets. Moscow's latest announcement indicates that the Kremlin now intends to answer those operations with a broader campaign against Ukrainian energy facilities.