Both British (80 AA Brigade) and US Army anti-aircraft batteries (30th AAA Group) were sent to Antwerp together with a searchlight regiment. The zone of command under the 21st Army Group was called "Antwerp-X" and given the object of protecting an area with a radius of 7,000 yards covering the city and dock area. Initially attacks came from the south-east, accordingly a screen of observers and searchlights was deployed along the attack azimuth, behind which were three rows of batteries with additional searchlights.