Without halting, the paratroops took the advance westward gaining ground up to Oued Zarga and meeting only medium opposition until they struck British paratroop columns ranging in the area. In the afternoon of 20th, Koch was forced to halt the advance, for his front was over-extended and his point unit was in danger of being cut off. Back in Medjez the Germans consolidated their gains and occupied a farm at Smidia to form the right flank of their thinly held perimeter. French counter-attacks came in during the night of 21st — Spahi horsemen mounted on Arab stallions — but these were driven off by machine gun and mortar fire. The area then entered upon a period of calm. The central region of the front, like the northern and the southern flanks, was sealed and behind the thin line of paratroops Nehring could form the army which would be able, given the supplies it needed, to hold the Tunisian bridgehead for some time.
The German commanding general was still deeply concerned with the weakness of his lodgement area and, to strengthen the Tunis bridgehead, divided it into a northern and a southern zone. An Italian force, under Loren-zelli, took over the southern part and Colonel Stolz, withdrawn from the Bizerta bridgehead, took over Tunis north. His command on the Bizerta front passed to Colonel Barenthin. Djedeida had by this time been established as the advanced air base and -Mateur as the sector from which German motorised patrols either probed the Allied front or guarded their own exposed and weak southern flank.
Although the machines of the Luftwaffe's transport command were still ferrying men and supplies across the Mediterranean, the slow-flying JU 52s had become the prey of Allied fighters. But sufficient men were arriving to thicken the perimeters and in Koch's regiment the supply of reinforcements brought the strength of 3rd Battalion to nearly 2000 men. By this time the 1st Battalion of the regiment had begun to arrive in the bridgehead and was posted southwards to take up positions near Pont du Fahs. During the night of 21st the advance parties of 10th Panzer arrived from southern France and took over paratroop positions in the Tebourba area and at Djedeida, leaving the paras free to reinforce their comrades in position around Medjez and at El Aroussa. The first thrust by American tank units in the El Aroussa sector came in during the afternoon of 21st and, although they seized the little village, their advance further eastwards ran into a strong defence manned by men of a motorised company from 104th Infantry, a flak detachment, and paratroops. The United States thrust was beaten back with heavy loss.
The first major, Allied offensive which was intended to capture the objectives of Tunis and Bizerta and thus fulfil the terms of reference for Operation Torch began on 25 November. The first target was Tunis, considered by the Allies to be the less important of the two perimeters. With the fall of that city the whole weight of Allied power could be directed to the capture of Bizerta.
The British plan foresaw that the main thrusts would be an advance to the line Mateur—Tebourba by the two infantry brigades of 78th Division supported by the mobile and mainly armoured Blade Force. To divert German attention from these main thrusts there were to be diversionary operations; the one a commando assault from the sea and the other an air drop on the southern flank.
The 36th Brigade of 78th Division was to advance from Djebel Abiod towards Mateur and then press onwards to seize a junction on the Mateur-Bizerta road. Possession of this would cut the" route between those towns and would form a base line for the final advance northwards to Bizerta. The 11th Brigade assault was to move upon and through Medjez el Bab and then strike north-eastwards towards Tebourba. Blade Force would be the mobile centre column protecting the left flank of 11th Brigade and be advancing upon Sid: Nsir. At that place it would turn due east, seize the Chouigui pass, debouch on to the plain at El Bathan and the aerodrome at Djedeida. Once Mateur and Tebourba had been taken the advance upon Tunis could begin.
The assault by 11th Brigade opened disastrously. Defending Medjez el Bab were three companies of Koch's 3rd Battalion, an Italian anti-tank gun detachment, a pair of 8.8cm guns, and some armoured fighting vehicles belonging to 190th Panzer Battalion. Signs of the impending British offensive had not been lacking and the Axis defenders stood ready for battle. The British pincer which struck from the north was made up of the 2nd Battalion The Lancashire Fusiliers and this unit made a night assault upon the town. In the bright moonlight Koch's men saw the extended line of British Fusiliers moving across the open plain and opened fire with terrible effect. The German paratroops had a higher than usual establishment of mortars and light machine guns which, when mounted on tripods, were converted into medium machine guns with a greater range. These weapons were also being handled by men who had years of training and combat experience and in the shon days of preparation had calculated the distances of objectives to a foot. The first mortar bombs of the barrage struck the Fusilier's battalion headquarters as it moved, with the rifle companies, across the plain to the west of Medjez and in the minutes which followed and under a storm of bullets and shrapnel, the Fusiliers were driven to ground.
The British advance was halted. There could be neither a going forward nor a going back and Koch's paratroopers made the British battalion suffer all through the night. A German barrage at dawn brought more casualities, but then the Fusiliers moved forward to the Medjerda river, determined to force a victory. The machine guns sited to fire along and across the shallow river caught the British infantry as they struggled to climb the crumbling banks and blasted them back across the Medjerda. The German paratroop commander seeing that the initiative now lay with him put in a sudden, determined counter-attack, which caught the Lancashire Fusiliers as they were preparing to withdraw to the start line from which they had begun the advance, and caused a certain amount of confusion. Later in the afternoon the German paras showed their potency when they attacked a British force at Djebel Bou Mouss, known to the British as Grenadier Hill, and located to the south-west of Medjez.
The threat of being outflanked by United States armoured forces nearing Goubellat forced Koch to evacuate Medjez el Bab and, covered by a rearguard furnished from men of No 10 Company, the Germans left the town after blowing the bridge. The British moved forward and occupied the deserted town. The paras then took up positions on both sides of the main highway to the west of Massicault. Near Bou Arada the 1st Battalion of Koch's regiment had been fighting against an Allied tank thrust and in short but bitter engagements had destroyed three armoured vehicles. The Allied attack was deflected and the armoured column turned back.
An American tank battalion, part of Blade Force, and numbering more than a hundred tanks in addition to other vehicles, moved out to reconnoitre the ground across which llth Brigade would progress after its capture of Medjez el Bab. The armoured battalion's line of advance lay through the Chouigui pass and to the west of that feature, just after noon, the United States armoured unit struck No 3 Company of Witzig's battalion. This group, which had formed the reserve for Brioch's division, had been reinforced with a troop of Italian SP anti-tank guns and sent up the line to hold the Allied assault.
In the face of superior numbers Witzig's men withdrew into the shelter of a walled farm which they defended tenaciously and held at bay the repeated assaults of the American tank men. With bursts of machine gun fire and sorties armed with explosive charges the German para-engineers obstructed the American advance and, having then fulfilled their purpose, slipped away in the hours of darkness.