By April 1944, Harris was forced to reduce his strategic offensive as the bomber force was directed (much to his annoyance) to tactical and transport targets in France in support of the invasion of Normandy. The transport offensive proved highly effective. By late 1944, bombing such as Operation Hurricane (to demonstrate the capabilities of the combined British and US bomber forces), competed against the German defences. Bomber Command was now capable of putting 1,000 aircraft over a target without extraordinary efforts. Within 24 hours of Operation Hurricane, the RAF dropped about 10,000 tonnes of bombs on Duisburg and Brunswick, the greatest bomb load dropped in a day during the Second World War.