The renewed attack on Cassino began on the night of 11/12 May, with HAA guns supplementing the artillery barrage (one regiment fired 23,000 rounds in a week), particularly for counter-mortar shoots. The brigade's LAA regiments were committed to bridges, defiles, assembly areas and artillery positions, and enemy aircraft were active in low-level strafing and bombing. There were severe problems in getting the AA guns forward along the heavily congested routes. X Corps in the mountains had little use for HAA guns, requiring LAA to defend vital bridges. XIII Corps, on the other hand, after crossing the Rapido river, advanced along Highway 6 up the Liri Valley (Operation Diadem) on a narrow front, with continual demands for HAA guns in the medium artillery role. 12 AA Bde found itself stretched along of roads protecting the long 'tail', though the "Luftwaffe" made only a few nuisance raids. After the breakout from the Anzio beachhead and the capture of Rome in early June, the Germans pulled back to the Gothic Line.