Gerd von Rundstedt

Another adverse factor was the way the Russians received continual reinforcements from their back areas, as they fell back. It seemed to us that as soon as one force was wiped out, the path was blocked by the arrival of a fresh force.

The German Air Force was not sufficient to protect the sea crossing on its own. While the leading part of the forces might have landed, there was the danger that they might be cut off from supplies and reinforcements.