LVIV, Ukraine (Reuters) – Some residents of Ukraine’s besieged city of Mariupol have resorted to escaping the blockade on foot as official evacuation efforts have mostly failed due to ongoing shelling by Russian forces, the region’s governor said on Friday. Some 400,000 people have been trapped in the strategic port city for over two weeks, sheltering from heavy bombardment that has severed central supplies of electricity, heating and water, according to local authorities. Russia denies bombing residential areas or targeting civilians. Speaking on national television, Donetsk region governor P…