The horror of Mariupol: Putin troops hold 500 hostages in a hospital as human shields while premature babies are abandoned by their parents – but at least 20,000 civilians have been allowed to flee the besieged city Around 20,000 civilians fled Mariupol along a humanitarian corridor, which runs to city of Zaporizhzhia Some 4,000 cars left Mariupol along the route in what is believed to be the bi..