KOSICE, Slovakia (Reuters) - Ukrainian Foreign Minister Dmytro Kuleba accused Russia on Wednesday of holding 400,000 residents of Mariupol hostage by shelling the southern Ukrainian port city despite efforts to establish a safe evacuation corridor for civilians.

       "Almost 3,000 newborn babies lack medicine and food," he wrote on Twitter. "Russia continues holding hostage over 400,000 people in Mariupol, blocks humanitarian aid and evacuation. Indiscriminate shelling continues."

       Russia has denied targeting civilians in what it calls a "special operation" in Ukraine.

       (Reporting by Max Hunder, Writing by Alessandra Prentice, Editing by Timothy Heritage)