Although Rommel had been ordered to simply hold the line, an armoured reconnaissance soon became a full-fledged offensive from El Agheila in March. In March–April, Allied forces were forced back and leading general officers captured. The Australian 9th Infantry Division fell back to the fortress port of Tobruk, and the remaining British and Commonwealth forces withdrew a further east to the Libyan–Egyptian border. With Tobruk under siege by the main Italian-German force, a small battlegroup continued to press eastwards. Capturing Fort Capuzzo and Bardia in passing, it then advanced into Egypt, and by the end of April it had taken Sollum and the tactically important Halfaya Pass. Rommel garrisoned these positions, reinforcing the battle-group and ordering it onto the defensive.