May 16 (UPI) -- President Volodymyr Zelensky Thursday visited Kharkiv as intense Russian attacks raged on Ukraine 's second-largest city, thanking defenders wounded trying to repel Russian invaders. He held a meeting of Ukraine's Supreme Commander-in-Chief's Staff in Kharkiv, according to Ukraine's state news agency Ukrinform. Zelensky said while conditions are "extremely difficult," the situation in the Kharkiv region is generally under control and Ukrainian soldiers are inflicting heavy