After nearly two months under siege, the southern city of Mariupol could fall into Russian hands within "hours", a Ukrainian official said Wednesday, as the two sides agreed to a humanitarian corridor to allow civilians to flee the devastated port city....The enemy is outnumbering us 10 to one," Serhiy Volyna from the 36th Separate Marine Brigade said."We appeal and plead to all world leaders to help us. We ask them to use the procedure of extraction and take us to the territory of a third-party state."Thousands of troops and civilians remain holed up in the plant.