The Australian anti-tank regiment, the 2/3rd Anti-Tank Regiment, was another victim of the British tendency to break up units and distribute their component parts. Two of the batteries had been at Mechili. They were mostly in Tobruk by 10 April 1941. Several sections had been lost in the collapse at Mechili, however. The 2/2nd Anti-Tank Regiment was experiencing the same sort of fragmentation. One troop headed to Sollum from Mersa Matruh. They were the anti-tank force with a column of troops from the 1/Durham Light Infantry. Major Argent's battery of the 2/3rd Anti-Tank Regiment reached Sollum and was told to report to the commander of the 22nd Guards Brigade. The plan in place at the time was to hold Sollum and Halfaya Pass for the next 36 hours and hold it "at all costs". The Australian historian notes that Major Argent's battery was still at the Egyptian frontier four months later.
One column from the Support Group encountered some enemy troops. Another enemy column (often mixed German-Italian troops) blocked the Bardia road east of Tobruk. The alternate spelling for Sollum is Salum, which is how the Australian historian refers to the place. Infantry and Australian anti-tank guns set up a defensive position at Halfaya, at the top of the pass.
On 11 April 1941, Rommel was directing operations at Tobruk. Colonel Schwerin took over command of General Prittwitz's group when he was killed. Elements of the 15th Panzer Division had started to arrive, so Rommel immediately directed some of them to move towards Salum. He had already sent the 3rd Reconnaissance Unit towards Salum. The 5th Panzer Regiment had been led to expect that when they attacked, the British would withdraw, which was just wishful thinking.
At Tobruk, General Morshead wanted each brigade to hold one battalion in reserve. The problem was that this was a great hardship due to the amount of perimeter each brigade held and the scarcity of forces. Tank and armored car units had to convert to infantry to aid in the defense. This is based on the account in Vol.III of the Australian Official History.