Operation Undertone

Operation Undertone ( German company Unterton ) was an operation of the 7th and 3rd US Army and parts of the French 1st Army from March 15 to 24, 1945, shortly before the end of the Second World War , with which the Palatinate , parts of Rhineland and the areas of northern Alsace and Lorraine , which were temporarily lost during Operation Nordwind , came under Allied control.

Allied forces broke through the last parts of the west wall still held by German troops and reached the Rhine on a broad front between Koblenz and Gambsheim and thus created the conditions for a crossing over the Rhine, after other Allied units had already reached the south on March 7th at Remagen had formed a bridgehead from Bonn (see Operation Lumberjack ).

Background, prehistory

Map of Operations Veritable / Grenade and Lumberjack

On December 16, 1944, the Germans began the Ardennes offensive . They succeeded in a surprise attack and an advance as far as Bastogne , which they besieged until December 27th . From then on the Western Allies succeeded in a counter-offensive; the German armed forces ( Wehrmacht , Luftwaffe ) suffered more every day from the lack of fuel, ammunition and much more. Nevertheless, they also started the Nordwind company (December 31, 1944 to January 25, 1945), an offensive in the Alsace-Lorraine region.

After the end of these two unsuccessful German offensives, the Allies faced the Siegfried Line , the Rhine and the Ruhr area . Operation Plunder , the Allied Rhine crossing, was already being planned. On February 13, 1945, General Dwight D. Eisenhower had ordered his two army group commanders, Omar Bradley and Jacob L. Devers , to begin planning a joint operation that would oust the Wehrmacht from the Saarland and Palatinate region . He told them to plan so that they would be operational on March 15th. The operation was only to begin after the British-Canadian 21st Army Group had reached the Rhine in the course of Operations Veritable and Grenade . The winter was extremely cold and long; one waited or hoped for more favorable weather.

On March 7, troops took the south of the 21st Army Group following the first US Army the 12th Army Group as part of Operation Lumberjack intact bridge over the Rhine at Remagen and established a bridgehead on the right bank, which Hitler took as an opportunity to Gerd von Rundstedt as Commander-in-chief West to be replaced by Albert Kesselring . The left bank of Cologne , one of the largest cities in the empire, was also occupied at the beginning of March. The Americans were now on the Saar and Moselle . Operation Undertone, the conquest of the Saar-Moselle triangle, was to form the next step of the Allied “Rhineland Campaign”, the advance on the Rhine on a broad front.

target

The aim of the operation was to drive the Wehrmacht out of the Saarland and Palatinate region , to pull enemy forces from the north to the south (or to bind them there) and to have an alternative area of attack in the event of the Allied advance in the north, Operation Grenade and Operation Plunder - should fail.

When General Eisenhower approved the plan, he noted that the goal was not only to drive the Wehrmacht out of certain areas (the Saarland and the Palatinate, referred to by Eisenhower as the "Saar-Palatinate" ( Gau Saarpfalz )), but also to that the 6th US Army Group would succeed in creating bridgeheads across the Rhine between Mannheim and Mainz . He also stated that the task of the US 12th Army Group (i.e., the 3rd US Army ) was limited to attacks in the divisional framework on targets along the Moselle in order to protect the left flank of the US 6th Army Group.

plan

During the first week of March, General Devers , commander of the 6th Army Group , approved a plan (Operation Undertone ) prepared by General Alexander Patch's 7th Army. Three corps were to attack on a front line between Saarbrücken and the Rhine near Gambsheim, southeast of Hagenau . A narrow strip that lay along the Rhine from the extreme northeast corner of Alsace near Lauterburg was to be conquered by units of the French 1st Army under the operational control of the 7th US Army. The greatest task was to be carried out in the central section of the front near Kaiserslautern .

According to the troop division by SHAEF , the 7th US Army of the 6th Army Group was to be reinforced to carry out the attack by one tank division and three infantry divisions of the 3rd US Army , while the remaining units of the 3rd US Army were to carry out a support attack.

In doing so, the German units in the Palatinate and North Alsace were to be cut off from their connections to the rear and destroyed to the west of the Rhine. General Devers' 6th Army Group stood by SS General Paul Hausser's Army Group G against.

Positions

General Jacob Devers

Everywhere along the Moselle between Trier and Koblenz the German 7th Army was in danger of being encircled or was attacked directly by the XX Corps of the 1st US Army under General Walton Walker . The collapse of the 7th Army was apparently only a matter of time.

Soon the German 1st Army was also in serious trouble because two days earlier - on March 15 - the US 7th Army had started an offensive on a 110 km wide section of the front between Saarlautern in a southeastern direction towards the Rhine. Even if the offensive to penetrate the western wall should fail, it could tie the troops of the German 1st Army to the fortresses while Patton's troops took them from behind.

When the US 7th Army's offensive began, it was questionable how tenaciously the Germans would defend before retreating towards the Siegfried Line.

Only General Milburn's XXI Corps (on the left wing of the army, near Saarbrücken) was quite close to the Siegfried Line; other units were up to 30 km away.

The main burden of the attack lay in the middle section of the front: General Wade H. Haislip's XV Corps stood in front of the town of Bitche . It was surrounded by fortresses of the Maginot Line . The Allies had tried in vain to take Bitche in December 1944 and had to evacuate the southern surroundings of the city and the entire area east of it between Lauter and Moder, but during a tactical retreat as part of the German company Nordwind .

On the right wing, General Brooks' VI Corps had to cross the Moder River; one of Brooks' divisions had to advance through the rugged northern Vosges.

Four Wehrmacht corps stood in the way of the American advance. Walter Hahms LXXXII formed the right wing . Army corps between Trier and Merzig . General Baptist Knieß 'LXXXV stood northwest of and near Saarbrücken . Army corps, which shortly before had handed over the 559th Volksgrenadier Division to the 7th Army and thus only had two divisions. To the south-east of the city stood on a section of the front that was roughly the same as that of Haislips XV. Corps agreed that the XIII. SS Army Corps with three divisions, commanded by SS-Gruppenführer Max Simon . To the left of this stood the LXXXX along the Moder up to the Rhine. Army corps under General der Infanterie Erich Petersen with two Volksgrenadier divisions and remnants of an infantry training division.

Although the Germans feared most that the opponents in the front section of Petersen's LXXXX. Corps would break through into the Weißenburg gap (rather than against Simon's XIII. SS Corps in the Kaiserslautern Corridor ), the troop shifts in the weeks before, which were supposed to strengthen the 7th Army, had the XIII. SS corps left stronger. In addition to two Volksgrenadier divisions , Simon's corps had the 17th SS Panzer Grenadier Division “Götz von Berlichingen” (at that time not much more than a proud name, but a unit that had significantly more tanks and armored vehicles than the whole other neighboring corps).

attack

March, 15

Course of the fighting in the Saar-Mosel triangle until March 21, 1945

The American attacks were aimed at the relatively strongest German units. When General Patch's 7th Army attacked before daybreak on March 15, it quickly became clear how the Germans were positioned.

Only in two places was there determined resistance:

on the left wing, where the 63rd US Infantry Division under Major General Louis E. Hibbs tried to bypass Saarbrücken to the east and cut off German escape routes from the city. The strong resistance was due to the fact that the 63rd hit the Siegfried Line early on.

far on the right wing, where the VI. US Corps attached 3rd Algerian Infantry Division (3rd Division d'Infanterie d'Algerie ) was supposed to clear the broad plains between Haguenau and the Rhine. There, an urban area on the Moder provided a line of defense and a flat ground free fields of fire for buried automatic weapons such as machine guns.

In other places, the resistance was sometimes tricky and difficult to turn off, but usually for a short time. There were many anti- personnel mines and anti-tank mines .

German artillery fire was light and sporadic. This was probably due in part to the fact that in the days before aircraft of the XII Tactical Air Command (Brigadier General Glenn O. Barcus) had flown attacks, on the cut-off date of the operation additionally supported by medium and heavy bombers of the 8th US Air Fleet on parts of the Western Wall, Zweibrücken and Kaiserslautern . The weather was very clear, so ideal for that. Those hit included Ia officers from two of the LXXXX's three divisions. Army Corps.

Of the units of the XV, enlarged to six divisions. In the US Corps, only one regiment of the 45th Infantry Division (Major General Robert T. Frederick ) had a water hazard at the start of the operation: it had to cross the Blies (a tributary of the Saar). The attackers broke through the German main line of defense before sunrise. With the help of searchlights, they bypassed defensive focuses and left them to advancing forces. In the evening the division was almost at all points 5 km across the Blies; only on a ring stand defense line near Saarbrücken and in the flat areas on the Rhine did it not make so much progress.

Right wing

On the right wing of the XV. Corps drove men of the 100th Infantry Division (Major General Withers A. Burress ) quickly to the foothills of the fortress town of Bitsch . Probably benefiting from the fact that they already knew the area from the fighting in December 1944, they achieved dominant positions on the fortified hills around the city; and there was no doubt that they would take the whole fortress the next day, March 16th.

The only significant German counterattack hit a battalion of the 7th Infantry Regiment of the 3rd Infantry Division .

March 16

On the second day, March 16, there were increasing signs everywhere except on the two flanks that the Germans were only fighting retreat. This appeared particularly clearly in the combat section of the XV. US Corps, where all three attacking divisions were able to build on their first day successes. The main obstacles were mines and pockets of resistance, which were mostly protected by tank or assault guns.

When night fell, the 3rd and 45th Divisions had advanced across the German border, very close to the outpost of the West Wall; and the 100th Division, fought free in Bitsch by a subsequent infantry division, had begun to follow suit at the same level of the front. XII fighter-bomber Tactical Air Command were back in action.

When the breakthrough of General Walker's XX. As US Corps progressed towards Kaiserslautern , fears grew among the 1st Army that German units could be encircled on the Siegfried Line and near Saarbrücken and Zweibrücken. If Kaiserslautern fell, these troops would only be able to retreat through the Haardt (a mountain range of the Palatinate Forest about 30 kilometers long, two to five kilometers wide and up to 673 m above sea level ). The Palatinate Forest was and is densely forested; it was only crossed by a main road, a side road just behind the Siegfried Line and a few small streets and paths. The natural difficulties of these winding, poorly surfaced roads were compounded by masses of vehicle wrecks as American fighter planes bombarded these roads non-stop.

March 17th: German units withdraw through the Palatinate Forest

After Kesselring had given permission on March 17th that units threatened by encirclement could withdraw, Hermann Foertsch , Commander in Chief of the 1st Army, allowed his most western troops to withdraw gradually: the LXXXV. Army corps under General Kniess. For three days, units of the corps were to march back from west to east and block the main road that led northeast through the Kaiserslauterer gap.

Unfortunately for Foertsch's plan, the main threat to the Kaiserslautern gap did not come from the west or south-west, but from the north-west. Walkers XX marched there. Corps unhindered by the LXXXII. Army corps under General Walter Hahm . The arrival of the 10th US Armored Division in Saarbrücken not only meant that the gap was endangered by a troop in the rear of Kniess 'line-up, but also that now the only way of retreat for Kniess' troops and those of the attached XIII. SS corps led through the Palatinate Forest .

March 19: through the main belt of the west wall

Operation Undertone marked the end of the American Rhineland campaign, followed almost immediately by the crossing of the Rhine.

As Knieß's retreat progressed, this had the effect of clearing a path through the Siegfried Line for the left wing of the US 7th Army. Despite fierce rearguard fighting, the 63rd Infantry Division of General Milburn's XXI Corps broke through the main defensive line near Sankt Ingbert on March 19, 1945 .

The plan was for Milburn to send an armored unit north to join Walker's XX Corps at Sankt Wendel ; but the advance of Walker's forces had been so rapid that all essential targets in Walker's sector beyond the western wall had already fallen. So at that moment you had no more targets to fight.

General Patch, the Commander in Chief of the 7th Army, took the opportunity to put additional pressure on the attack of the XV Corps through Zweibrücken in the direction of Kaiserslauterer Lücke, the main attack of his army.

The divisions had two days against the XIII. SS Army Corps fought under General Simon, but no breach for armored vehicles through the Siegfried Line has yet been made. Patch ordered General Haislip (the commanding general of the XV Corps) to advance through the gap left by the 63rd Division and attack the Siegfried Line defenders who were fighting the XV Corps from behind.

It was obvious to General Foertsch that the Americans would take advantage of the loophole created by his withdrawal. During the night of March 19, he extended his withdrawal order to the western wing of the XIII. SS Army Corps.

March, 20th

On the night of March 20th the rest of the SS corps began their retreat; this enabled the 3rd US Division to move forward more quickly.

On March 20, the Luftwaffe sent about 300 aircraft of various types, including the jet-powered Messerschmitt Me 262 , to attack the marching columns of the 3rd US Army. They caused only minor losses. American air defense units (giving them the rare opportunity to use what they had trained) shot down 25 German planes; XIX Tactical Air Command pilots reported eight kills.

rating

Although all divisions of the American VI Corps made their breakthroughs on March 23, they only came into contact with rearguard associations and did not succeed in significantly affecting the German evacuation. Because a German unit fought doggedly in Speyer , contact between the 12th and 14th US armored divisions was delayed. Early on March 24, both armored divisions sent commandos towards the Germersheim railway-Rhine bridge , but none had reached the city when the Germans blew up the bridge at 10:20 a.m.

7th Army personnel estimated that the two German armies lost 75–80% of their infantry during Operation Undertone. The 7th US Army and its affiliated French units took 22,000 prisoners during the period; the 3rd US Army captured over 68,000 German soldiers.

The 3rd US Army recorded 5,220 casualties, 681 of them dead. The armed forces units opposing it lost about 113,000 men (including the above-mentioned 68,000 prisoners of war). The 7th US Army, which fought mainly on the Siegfried Line, probably had about 12,000 casualties, including nearly 1,000 fallen.

literature

Charles B. McDonald: The Last Offensive . GPO, Washington 1973, chapter 12
État-Major de l'Armée de Terre: Les Grandes Unités Françaises . Vol. V-3, Imprimerie Nationale, Paris 1976
Mary H. Williams (ed.): Chronology 1941-1945 . GPO, Washington 1994