Ukrainian officials on Monday morning reported a massive barrage of Russian strikes on critical infrastructure in Kyiv, Kharkiv, and other cities.

Part of the Ukrainian capital was cut off from power and water supplies as a result, its mayor Vitali Klitschko said. Officials also reported possible power outages in the cities of Kharkiv and Zaporizhzhia resulting from the strikes.

The attack comes two days after Russia accused Ukraine of a drone attack against Russia’s Black Sea Fleet off the coast of the annexed Crimean peninsula. Ukraine has denied the attack, saying that Russia mishandled its own weapons, but Moscow still announced halting its particiaption in a U.N.-brokered deal to allow safe passage of ships carrying grain from Ukraine.