KHERSON, Ukraine, June 7 (Reuters) - Ukrainians abandoned inundated homes as floodwaters crested across a swathe of the south on Wednesday after the destruction of a vast hydro-electric dam on the front line between Russian and Ukrainian forces that each blamed on the other. Kyiv said on Wednesday its troops in the east had advanced by more than a kilometre around the ruined city of Bakhmut in eastern Ukraine, its most explicit claim of progress since Russia reported the start of the Ukrainian offensive this week. For its part, Russia said a Ukrainian drone had struck a town on the opposite bank during evacuations there and accused the Ukrainian side of continuing shelling despite the flooding