Ukraine’s President Volodymyr Zelensky warned on Sunday against more potential Russian attacks on energy infrastructure, while the mayor of Kyiv urged residents to consider preparing to leave temporarily if the capital lost water and power supplies. Zelensky said Russia was “concentrating forces and means for a possible repetition of mass attacks on our infrastructure. First of all, energy.” More than 4.5 million consumers were already without power, he added.

U.S. national security adviser Jake Sullivan, who was in Kyiv on Friday held undisclosed talks with Russian officials designed to avoid further escalation, Wall Street Journal said on Sunday. The Kremlin on Monday declined to comment that Washington held the talks with Russian officials.