Ukraine is taking out oil refineries inside Russia, cratering Moscow’s supplies and sending local prices soaring.

A wave of Ukrainian drone strikes on oil refineries deep inside Russia has left the Kremlin racing to defend its own territory while still waging war on its neighbor. But the attacks have also achieved the unthinkable — leaving the world’s largest petrostate running low on petrol.

Diesel prices for Russian consumers have skyrocketed, rising almost 10 percent in the past week alone, according to the government’s figures. Petrol costs have also hit a six-month high, up more than 20 percent from the start of the year as supply tightens and more and more facilities are forced to suspend production.

Last Wednesday, two fuel storage facilities owned by Russian energy giant Rosneft, around 500 kilometers from the border with Ukraine, were severely damaged by drones as fuel went up in smoke. More than a dozen refineries across nine Russian regions have been similarly hit this year, with officials in Kyiv saying the industry is a legitimate war target.

“It’s like a mosquito — when you can’t find it, can’t kill it and it keeps coming back night after night, you’re going to be exhausted," Philip Ingram, a former British military intelligence officer and NATO planner, said. “It’s a very good way of taking the pressure off from the front lines."