President Zelensky appeared on the streets of Kiev early Saturday during a pause in artillery fire and all-night fighting between Russian and Ukrainian troops. A power station north of Kiev was captured. Ukraine’s army said it had repelled a Russian attack on one of the capital’s main avenues. Hundreds of casualties are reported. A shelling sliced through a high-rise Kyiv apartment building. Clashes continued in other cities. The Russian Defense Ministry reported the fall of the southern port of Mariupol. Ukrainian sources said the port and other cities were struck by cruise missiles from the sea. Clashes continue in Odessa.