Ukraine struck a railway depot and knocked out power in the Russian-occupied city of Melitopol deep behind the front line on Wednesday amid growing talk from Kyiv of a counterassault against Russian forces worn out by a failed winter offensive. Unverified images on the internet showed explosions lighting up the night sky with streaks of contrails in Melitopol, base of the Russian-controlled administration in Zaporizhzhia, one of five Ukrainian provinces Russia claims to have annexed. Ukraine's exiled mayor of the city confirmed there were explosions there. Russia's state TASS news agency, citing Moscow-installed officials, said a railway depot was damaged...