Despite more than a year of warnings that critical Ukrainian nuclear energy infrastructure sites are vulnerable to potential Russian attacks, Ukraine's Energy Ministry has failed to act swiftly to protect them, government officials have told The Associated Press. Only in the fall, after Ukrainian intelligence agencies warned of potential strikes targeting nuclear transmission facilities, was action taken to begin building protection, the officials said — far too late in the event of an attack. Russia's renewed attacks this winter have heightened scrutiny over these failures. Two years of punishing Russian strikes on its power grid have left Ukraine reliant on nuclear power for more than half of its electricity generation.

KYIV, Ukraine (AP) — Russian forces escalated their attacks on crowded urban areas Tuesday, bombarding the central square in Ukraine's second-…