Thousands of people were successfully evacuated by buses from the besieged Ukrainian city of Mariupol on Friday, according to Ukraine’s President Volodymyr Zelenskyy, who called the situation there a “humanitarian catastrophe.” Zelenskyy said in a video address early Saturday that a humanitarian corridor was operational in Zaporizhzhia, allowing for the evacuation of 3,071 residents from Mariupol. Tens of thousands of people have been trapped in the besieged city, with scant access to food and water. The Red Cross said that its team tried to facilitate safe passage out of Mariupol on Friday but they had to turn back and return to Zaporizhzhia after encountering conditions that “made it impossible to proceed.” “We will try again tomorrow,” the Red Cross said, adding that, “it’s critical the parties respect agreements and provide the necessary security guarantees.” On a number of occasions, Russia and Ukraine have agreed to humanitarian corridors to facilitate the …