German 6th Army broke through the Dyle Line; British troops withdrew west of Brussels and the Belgian government evacuated to Ostend. From its Meuse River bridgeheads, German Army Group A tanks broke through the French lines, capturing thousands of surrendering French troops. Guderian's units reached Montcornet, while Rommel's units reached Avesnes-sur-Helpe. Fearful that this advance into France would expose the invasion's flanks, the German High Command ordered Army Group A to halt its spearheads so that the infantry could catch up
