Russia conducted a “massive” attack against Ukraine’s energy infrastructure on Thursday, firing nearly 200 missiles and drones and leaving more than a million households without power, Ukrainian officials said. Russia’s second major aerial attack on Ukraine’s power grid in less than two weeks amplified fears that the Kremlin aims to cripple the country’s power generation capacity before winter.

“Attacks on energy facilities are happening all over Ukraine,” Energy Minister Herman Halushchenko said in a post on Facebook. He added that emergency power outages were implemented nationwide. In some regions, Kalibr cruise missiles with cluster munitions smashed into civilian targets, Ukrainian President Volodymyr Zelenskyy said, calling it “an insidious escalation”. Cluster munitions release numerous small bombs over a wide area, making them dangerous to civilians both during and after an attack.