Moscow has increasingly hit critical substations linked to nuclear power plants in an effort to disconnect them. The assaults risk a disaster, experts said.

The war between Russia and Ukraine is intensifying with new attacks and new concerns over the weapons being used by both sides. Vladimir Putin says Russia’s use of a nuclear-capable weapon is a response to Ukraine firing American weapons deeper into Russia for the first time.

Ukrainian officials say Russia has conducted a “massive” attack against Ukraine’s energy infrastructure, firing nearly 200 missiles and drones and leaving more than a million households without power