In the autumn of 1944 the Soviet 2nd Ukrainian Front broke through the Transylvanian Alps and into the central Hungarian plain and by the end of October had already reached the Danube river below Budapest. The Danube, with high water levels from recent rains and swampy banks was potentially a major barrier, and could have acted as a formidable break to the Soviet advance, and a considerable defensive asset if the Axis powers had forces enough to man it. But the bulk of German major formations in the country were falling back into northern Hungary to protect the capital, and Army Group F, given responsibility for lower Hungary had little with which to stop the Soviet Red Army advance. The Soviet 57th Army reached the river and quickly threw 2 bridgeheads across at Mohács and Baja. Army Group F could only erect a fragile screen around the Soviet bridgeheads, and call for reinforcements.