LVIV (Reuters) - The Ukrainian port city of Mariupol is suffering mass casualties and a water outage as it defends itself from a nonstop onslaught by Russian forces, Mayor Vadym Boichenko said in a live broadcast on Ukrainian TV on Wednesday.

       "The enemy occupying forces of the Russian Federation have done everything to block the exit of civilians from the city of half a million people," he said.

       He did not provide an exact casualty figure.

       (Reporting by Natalia Zinets; Writing by Alessandra Prentice; editing by John Stonestreet)