First Army in southern Tunisia. The supply situation was a little better, with tons of the required daily, but of the fuel had been used distributing supplies or in retreat. The Long Range Desert Group (LRDG) attacked Axis supply lines and hundreds of lorries were stranded along the roads for lack of fuel, while the Eighth Army amassed fuel and ammunition for its next attack. On 13 January 1943, the infantry of the 21st Panzer Division were sent north to the 5th Panzer Army to protect Gabès. On 15 January, the Eighth Army attacked with against and tanks. That evening Rommel ordered another retreat; lack of fuel and apprehension about the threat to Gabès, led the retreating infantry to pass beyond the Tarhuna–Homs line. The British occupied Tripoli on 23 January (the Axis retreat from El Alamein had covered . On 13 February, the last Axis soldiers left Libya and on 15 February, the rearguard reached the Mareth Line, inside Tunisia. intended them to hold the line indefinitely but Rommel considered it too vulnerable to another flanking move, unlike the Wadi Akarit position further back. Terrain The broken terrain of southern Tunisia, with difficult rocky ridge lines and desert, limited manoeuvre; opposite the bight where the north–south coast opens to the east, a semi-arid, scrub covered coastal plain is met inland by the Matmata Hills which lie south to north. Across the plain in a line roughly south-west to north-east was the Mareth Line, fortifications built by the French in the 1930s. In the north, the hills and the line of forts ended at the Tebaga Gap, a mountain pass between the Matmata Hills and the Djebel Tebaga, another line of high ground to the west of the gap, running east–west. North and west of this feature is the Chott el Djerid and west of the Matmata Hills, dry country and then the impassable sand of the Grand Erg Oriental. Gabès lies on the coast, where the plain meets the route from the Tebaga Gap. North of Gabès, the road to Sfax passes between the sea and the chotts, was the only route north for the Eighth Army and it was blocked by the Mareth Line. The Mareth Line followed the line of Wadi Zigzaou, a natural tank obstacle with steep banks rising up to high; the north-west side had been fortified by the French and subsequently reinforced. The wadi