so far they control odesa but mariupol remains on the brink with russia controlling all but one steel plant complex. cnn s jim sciutto reports on the struggle for survival in mariupol. reporter: evidence of new horrors emerging from the desperate ukrainian stand-off in mariupol. satellite shows what appears to be a massive grave just outside the city. local officials accuse russian officials of war crimes there. russian president vladimir putin has claimed russian forces liberated mariupol and says he personally called off an assault on the azovstal steel plant. the u.s. is not convinced, however, that russia controls all of the city and ukrainian officials denial it. actions. not words. we have to watch and see what the russians actually do here. reporter: ukraine says russia has not agreed to establish civilian corridors to allow