A convoy of at least 160 cars left Mariupol on Monday in the first successful attempt to arrange a humanitarian corridor out of the encircled Ukrainian city after over a week of trying. Civilians have been trapped in the southern port city by Russian shelling for more than two weeks and have been without heating, electricity and running water for most of this time, the Ukrainian authorities say. More than 2,500 residents have been killed there since the Russian invasion on Feb. 24, a Ukrainian official said.