By Andrew Osborn MOSCOW (Reuters) – The head of a Russia-dominated military alliance that is sometimes called Moscow’s answer to NATO has said his organisation could send peacekeepers to territory in eastern Ukraine controlled by Russia-backed rebels if needed. The situation in two self-proclaimed pro-Russian republics in Ukraine’s Donbass region is on a knife-edge after rebel leaders declared a full mobilisation of their forces and asked civilians to evacuate to Russia following shelling which Ukraine and the separatist rebels blame on each other. In an interview conducted before that evacuat…