In desperation, some Jewish leaders asked the Allies to bomb the railway lines  leading to the extermination camps and even Auschwitz itself. The response…was negative…In fact, Allied aircraft  were already flying over Auschwitz, bombing nearby industrial targets and dropping supplies to the Polish resistance in Warsaw….In the end, it is hard to escape the conclusion that the Allied failure to do more to save Jewish lives derived not merely from a lack initiative but also lack of sympathy.

Tim Bouverie Allies at War pp438-9