The 96-missile barrage fired across Ukraine on Tuesday was Russia’s biggest aerial attack of the war so far. But it followed months of assertions by Western and Ukrainian officials that Moscow’s stockpile of missiles and other weapons was rapidly dwindling.

Whether the assault on infrastructure targets was long planned, as Ukrainian commanders say they believe, or served as a deadly response to Kyiv’s recapture of the city of Kherson last week, the widespread attack raises questions about how much Russia’s arsenal may be depleted and whether Moscow will endure by finding alternative sources of weapons.

The Ukrainian defense minister, Oleksii Reznikov, said last month that Russia had burned through nearly 70% of its prewar cache of the kinds of missiles that were largely used in Tuesday’s attack: Iskander, Kalibr and air-launched cruise missiles. At the time, Reznikov said Russia had only 609 of those missiles left, although none of the figures could be independently verified.